The stadium facilities available to clubs will become more and more a case of the haves and have-not's over the coming decade. Those clubs playing out of the more advanced venues will have a greater chance of drawing casual spectators and converting them to regular attendee's and will have a huge advantage in drawing corporate support where a premium can be made. Not to mention the differences in Gate Reciepts.
One of the best ways to ensure that the government keeps the grants to your clubs stadium flowing (besides being located in a marginal seat) is for the venue to accommodate as many tenants as possible.
More games being played = more spectators = a higher return on the governments continual investment.
There is a clear correlation between the number of games hosted at a venue and the amount of government money spent on upkeep and upgrades.
Take the "Big 3" NRL grounds for example:
Suncorp Stadium: Broncos, Reds, QLD Roar, NRL Origin games, NRL Finals Series
Telstra Stadium: Rabbitohs, Dragons, Parramatta, Tigers, Bulldogs, Swans, NRL Origin games, NRL Finals Series
Aussie Stadium: Roosters, Warratahs, Sydney FC, NRL Finals Series
Other NRL grounds that cater for more than one tenant:
Gold Coast Stadium, Robina (2008): Titans, Gold Coast Galaxy ('09), Some Union
EAS: Newcastle Knights, Newcastle Jets FC
Canberra Stadium: Canberra Raiders, ACT Brumbies, likely venue for a Canberra A-League club.
Central Coast Stadium: Central Coast Mariners FC, 7 NRL games in '07
NRL grounds that cater for the one club:
Dairy Farmers Stadium*
Brookvale
CUA Stadium Penrith
Oki Jubilee Stadium # (no games this season)
Toyota Park, Cronulla
WIN Stadium*
Campbelltown Stadium
Leichhardt Oval
Parramatta Stadium # (reduced by a further 2 games this season)
* Indicates a stadium that has been earmarked as a home ground for an A-League team.
One of the keys to the Storm getting a new stadium was Melbourne Victory FC committing to be co-tenants, (hopefully) securing Melbourne's long term financial viability in the NRL.
Clubs that are currently splitting their home games between multiple venues are going to have to bite the bullet soon and primarily committ to a single venue. With the facilities required for an NRL team, venues that host half a dozen top flight games won't be able to atract the funds to keep them up-to-date and quickly be relegated as not up to scratch.