Even those on relatively high salaries, who don't expect their earnings to rise, will have to think twice about whether it makes sense to continue with contributions.This presents scheme managers with a dilemma - they have to keep the deal sweet enough to retain members and attract new ones, a problem that becomes much more urgent when a scheme is in deficit. When that happens, the whole thing is at risk of being sustained by promises that managers cannot ensure they will be able to keep.
To be honest, I think the UCU is obstructing the necessary dose of bad news that will be necessary to ensure the USS's sustainability. One problem that's come up: the USS's 3rd-largest equity holding is BP, with a market value of 693.7M (the list I got that information from is updated only every 3 months, so BP is likely to be lower-down by now.) USS has a total of about 22Bn in invested capital. (Not that I blame them for owning some BP. It looked like a good bet a few months ago.)
Here's a quote from that UCU question-and-answer page.
Q: Aren't all public sector pension funds going to have to make changes to save money. Whys should academics have special treatment?
A: USS is not a public service pension scheme, so it has to meet the same targets as other funded occupational pension schemes in the private sector. Its big advantages over such schemes are that the HE sector as a whole is less likely to go bust than any individual group of companies, so that it can afford to take a longer view. That does not mean that the politics of envy will not give traction to attacks on USS; but that is no good reason for the preemptive cringe that is part of what characterises the stance of the employers' negotiators.
Full marks for emphasizing that the USS is not public-sector, but the usage of "politics of envy" made me cringe. Finally, here's a fragment of the USS investments page to show that in some respects they have impeccable taste.
(It's the Go game that caught my eye.)