The Salary Cap hasn't kept pace with inflation. When they brought in a Salary Cap in RU they did so on the basis that they would raise it over time, which they did. That wasn't the intention in RL and reflects the lack of ambition of those running the game and an unwillingness to pay our talented athletes wages comparable to those in other sports.
The Salary Cap hasn't brought financial stability to the game. Lots of clubs have gone bust in the Salary Cap era; other clubs are struggling, for example even in their new stadium Saints continue to post big losses.
The Salary Cap is indefensible in its current form. It has unfairly reduced players' wages in real terms and hasn't stopped clubs overspending in other areas and getting into financial difficulties, while at the same time disincentivising clubs from increasing revenue and investment.
The Salary Cap has been very damaging to the sport. If we carry on like this I think we need to accept that there will be a further decline in the game, there's a real danger in the long term of English RL ending up more like French RL in status than the sport we have today.
It would be great if a club owner, perhaps in conjunction with the players' association, brought a legal action for restraint of trade. It's clear now that the SC is an unreasonable restraint of trade.
Clubs need to be subject to financial controls, but we need a much better system than the SC.
We've known this for a long time, though, so I doubt anything will change.