A lot of anti-News Ltd people will point the 1995, the SL war and WRC causing them to go pro.
This is not the case.
The reasoning behind RU going professional dates back to early 1994.
the UK signed itself up to a whole bunch of EU laws, including anti-discrimination... and it involved the bit where no body can receive government funds if it implements certain forms of discrimination.
One of these anti-discrimination protection rulings was freedom of association.
How this impacted on RU was that if a RU body banned a player for going to RL, that player could sue them if they wished to return, thus the sporting funding received from the governments would have to be withheld. Obviously RU could no longer ban players.
Therefore if they remained amatuer, any RU player who wanted to try a pro career could easily walk into a RL club, try his hand at it, and if successful.. sure they could stay, and if they found out it wasn't for them, freely return to RU with no fuss.
Thus to prevent all the talent going to RL, RU decided to go professional as well.