**Made alterations after noticing some terrible grammar**
I'm amazed at how simple the people in this forum are viewing this issue. Simple fact of the matter; everyone here is Australian.
The 2006 Football World Cup generated $6,000,000,000 ($6 Billion) in revenue for the host nation Germany. Furthermore; $2,000,000,000 ($2 Billion) was spent in preparation for the World Cup.
Benefits that this type of project can provide Australia with can be better understood when you fragment the benefits beyond the simple interests of a sporting code. Imagine $2 billion (being spent preparing for the event). Imagine $6 billion in foreign money entering Australia. This is a lot of money. (I'm not sure what this compares with in terms of national GDP - but its more money than I will probably ever see

) What could be done with $6 billion to improve Australia.
Consider how Australians would benefit from the capital expenditure prior to event. From construction, electricians, plumbers, accountants, to accommodation providers, tourist and travel organisations, restaurants, etc...etc..etc..Endless Now, does League, Union, AFL, Cricket, etc....deserve $6 billion worth of protection from Football for an 8 week period?
Hostility from uniformed passionate supporters of different sports isn't unexpected from a nation with divided interests. They fail to realise the full scope of benefit this event provides to their nation.
Fortunately impartial minds will decide this decision.
Simple Explanations for World Cup Demands
1. Why can't we play at the same time. Is the FFA FIFA scared?
I don't think the FFA or FIFA will be concerned about crowd attendance or viewer numbers in Australia. Suffice to say each match will likely be sold out.
It becomes an issue of logistics coupled with global attention. Police are needed for law enforcement, public protection. During the World Cup; huge numbers of tourists are anticipated through all major cities from all competing nations not to protect players, press, etc.
Spreading officers between tourist influxs, normal public duties as well as domestic sporting events such as the NRL could result in lack of staffing to support an emergency situation.
2. Why can't we use the fields before and during the competition?
Think insurance. These players are insured by clubs, nations, privately for incredibly large sums of money. (I wouldnt be surprised if some are insured for upto $100 million -heresay). Thus each field must be provided in immaculate condition. This means no Rugby matches on the field, no dug up holes, etc.
Furthermore sponsorship revenues from these matches is insanely high. Even the slightest hint of "Telstra" on the middle of the field would change the result of these earnings - satisfaction of sponsors.
3. Why do they need so many fields?
32 teams compete in the World Cup. Each team needs to be provided EQUAL level support to ensure parity in competition. This means each team requires equal levels of training facilities, access, support - at an adequate level to ensure that the best team wins each match. (Consider that most teams spend 2 years preparing for the World Cup - with half only playing 3 matches).
Simplified: Wallabies versus All Blacks: would you be ok with the Wallabies using a dirt field whilst the All Blacks prepare on a high quality game field? No. Parity is important.
This is also an important issue for gambling. Preparation before the match is a vital component of the teams performance. Discrepancies in training facilities can cause irregularities in this important aspect of the sport.
4. NRL will suffer at the hands of Soccer.
Correction, its Football. *The real kind.
However most importantly, I consider myself an Australian before I support any code or club(brand). Example: I'm a firm Atheist, I live in Sydney and work in the city. For 2 weeks in 2008 I dealt with what I believe are superstituous, delusional beliefs for World Youth Day. However I respected the fact that they were pumping millions into the Australian economy. Thus I supported the event.
You might not like Football, but are you Australian enough to support Australia as well?
Finally; what you should be concerned about...
I understand the concerns of contact sports in Australia. Some of the issues I think might explain some of the issues in League, and its position related to Football are:
Traditional Grassroots Rugby League, Union, Cricket, AFL numbers have diminished over the past 10 years in Australia. Football is the clear winner. This trend if it continues will result in the 20-40 age bracket being predominantly more interested in Football than League. the 40+ men are more involved with contact sports. I've witnessed this trend first hand; playing Football (Mediterranean Descendant Ball) and being beaten, taunted for being heavily involved in it (despite the fact that each lunch all these kids played football with me anyway

)
Reasons for this are suggested to be caused by:
(Without any vindictive meaning in these racial comments): Its a safer, more enjoyable, technical challenging sport.
Increased participation from Pacific Islanders in contact sports has pushed younger children from other backgrounds away. This is due to Pacific Islanders naturally developing faster in comparison with other children. This provides these children with an extreme advantage; making the sport "unfun" and even dangerous. Being brutally pushed out of the way, without any need for technical talent doesn't reward kids. (Especially towards teenage years).
These 2 trends can be viewed in current competitions. The growth in Pacific Islanders in professional sports is comparatively larger than in Football. (However I believe Tim Cahill is Samoan right?)..
Whereas the "Australianisation" of Football in Australia is noticeable by looking through their origins. The massive improvements in quality of Australian Football (domestic and international) are remarkably obvious. Australian children arguably prefer Football as their preferred sport. Children are typically more familiar with Football players David Beckham, Cristiano Ronaldo, Tim Cahill, Harry Kewell than Fuifui Moimoi, Jarred Hayne, Sonny Bill Williams, etc..Children are more likely to be involved in playing the sport.
Consider if this trend continues for another twenty years. This means that the 20-40 cohort of today will become the 40-60. Combined a stronger 20-40 its likely Football will achieve this position irrespective of the World Cup.
Attendance Figures: the problem with A-League attendance compared with NRL is two-fold. Firstly, the NRL is the pinnacle of this type of sport. This is as good as it gets. Secondly, Australian Football suffers at global competitiveness of the Football industry. Australian talent goes overseas to play in more professional leagues receiving millions in compensation. Furthermore, it competes with the English, Spanish, Italian, German Domestic Leagues as well as the Champions League. Break down the number of Football matches that are watched in Australia and it will give a true indication of the followship of this sport (all without any considerable FTA).
I'm not familiar with how League performed - but I would suggest their is room for improvement; especially considering that NRL (not sure how the English Superleague rates): competition for this type of competition. Watching the telecasts on TV; there were many matches were it looked like attendance was pretty questionable.
Oh and finally - culture - obviously off-field dramas don't need to be brought up. But 2009 was a pretty unusual year in League.