I can't confirm that there are fewer upgrades. On my last vacation I stayed in 4 hotels. In one I had the largest One Bedroom Suite anyway and I booked "regular". So that doesn't count. In 2 Belmonds I got upgrades with Bellini/ Virtuoso as far as I can see (once I'm sure, in the other case they didn't tell me the category, but it might have been one above). At the Four Seasons Surfside I got an upgrade of 4 categories and worth nearly 2000 $ with FSPP to a Studio Suite (though suites are supposedly exempt), so can't complain there either.
Last year was also similar to the years before, whereby I had booked relatively many hotels that do not belong to Virtuoso / FHR, etc.. Where upgrades were "to be expected" (especially at smaller hotels I often book the largest suite from the outset) I had success, for example at the FS Paris in the suite area (still worth 2000 € per night), at the Lanesborough (even guaranteed above the Junior Suite), Brenners and Schloss Elmau.