>Isn't adjusting retirement benefits down a form of tax hikes?
no, it isn't
in fact as far as we know budget adjustments done on the spending side have better performances as a rule of thumb than in the revenue side (tax hikes), see Alesina
>accepted across the entire economic spectrum
I did a search for "austerity" on Amazon and found this book by three econ profs that takes a look at a large number of cases and finds that spending cuts work better than tax increases when government finances are spiralling out of control, and don't harm growth.