FWIW on your (5) there's nothing unsustainable about the most recent iteration of the pension scheme. The problems are an interesting (if infuriating) combination of the employers wanting to kill the defined benefit scheme to save money, the government's regulatory framework being designed to protect pensionholders in closed defined benefit schemes and not to run functional private DB schemes (which are nearly all gone), the Trustee company being untrustworthy, and the governance arrangements being poor. The only people really committed to the scheme continuing are its members, for whom it's theoretically run but in practice have very little control over it.

If you want an illustration of the magnitude of the problem the might resonate with HNers: the USS Trustee is aiming to achieve CPI+0% investment returns for the next 40 years. With long-run equity returns being what they are, that's borderline criminal. (It's certainly not the investment strategy that universities will be adopting for their own endowments).

The honest truth is that the USS was highly solvent on a going concern basis before the recent changes (which already involved prospective cuts of 30% to accruals only a few years ago). It only generates a deficit if you model closing the scheme tomorrow and shunting the entire fund into gilts in order to eliminate all investment risk. But even if you do that, the scheme can still pay: it's explicitly backed by the combined assets of every scheme member, which includes all the richest universities and (hilariously) the government.

Oh, and the present cuts will take it down to less than half the pension of our colleagues in the newer post-92 universities who are in the Teachers' Pension Scheme. What price a formal government guarantee?