For the rest, it seems like that if his objection 1 holds that 2 is vitiated. If Social Security only grants enough to keep people out of destitution, or to put it another way, grants the retirement currently given to those in working class, then the middle and upper class still have reason to save. If everyone is guaranteed the same low minimum income, then there is no moral hazard. Even if people only end up with the low minimum income if they really need it, then the moral hazard is still low because the retirement income would be much lower than those middle and upper class people could make by investing safely.

Of course, if we "fix" his problem with #1 and ensure that people get a good wage replacement rate guaranteed, so that the middle class and upper class are guaranteed middle and upper class retirement incomes, but then add add-in accounts, moral hazard becomes very real.

1 and 2 are arguments against add-in accounts, surely. They are not arguments at all against progressive inflation.