You give the impression that clubs in English RU going bust is a big problem. I know Wasps were in bother last year and it looks like London Welsh could be after their backer has pulled out but I can't think of any others in the top two competitions in recent times. So no more really than in RL.
I just find it amazing that Championship RU appears to have a higher cap than Superleague.
You can understand Koukash's issue, that the current cap levels will be placing some major limits on who he can recruit, even though money is no issue for the club. I presume he got involved with Salford to win things, generally you need the best to win trophies and more often than not the best cost money. It could be argued the current low cap level is a big disincentive for people from outside the sport to invest their money in RL as it places a major restriction on the assembly of a competitive team of top talent in the short term. Which is probably what is needed at Salford.
The simple fact is that Rugby League has a cap that matches it's levels of income. Rugby Union has one that matches it's level of income.
The difference in turnover between RU clubs and RL clubs is staggering, especially when you look at the crowds.
As long as Union fills massive stadiums in London, Edinburgh, Cardiff, Dublin and Paris on a regular basis, and we struggle to fill Wigan, Hull, Huddersfield and Leigh, then they will always be richer.