The current title of this thread ("Bye bye to suites") suggests that suite upgrades are going away (or that suites are going away).

All that's gone away is a bit of language that has caused unrealistic expectations. The old wording in the T&Cs promised too much.

I don't expect anything to change. Whether I book a low category room or a higher category room, I generally receive an upgrade of a category or two above what I booked. It's seldom an actual two-room suite (unless I use an NUA), but occasionally it is.

The number of true premium rooms and suites varies widely by hotel. It's not unusual for a Marriott Bonvoy property to have dozens of elite arrivals on the same day -- and an inventory of cookie-cutter rooms differentiated primarily by floor and view, with perhaps a few larger rooms and a handful of suites. Not everyone will get a big executive corner suite on the top floor.

Hotels that know that it's good business to keep elite members loyal to Marriott Bonvoy properties will continue to provide good elite recognition. Hotels that consider elite members to be costly nuisances will continue to provide poor elite recognition (and will continue to deprive other Marriott Bonvoy properties of future business). Fortunately, I've stayed at far more of the former than the latter.