It absolutely is a huge mistake. There is no incentive to get out in the field, which is what the event is all about. When 3/4 of the participants (that's about what it's up to currently, BTW) are sitting at home, kinda defeats the purpose of Field Day, does it not? Might as well just change it to Home Day and have everybody sit at home, like every other contest. There's no way you are going to convince me that 3/4 of the participants are not able to get out and about. That's utter nonsense.
Not sure how you run FT8, but our FT8 station was manned all 24 hours, with a minimum of 2 people, usually 3. No different than banging out CW or working SSB as far as I'm concerned. And in fact, it takes considerably longer to make a QSO.
Just to correct myself, most of my FT# contacts were FT4 (which admittedly is a little more tolerable than watching paint dry). But, there were just so many FD stations on the FT4/FT8 subbands that I couldn't ignore them all. It still is a zombie mode. Click with the mouse once, make a QSO, rinse & repeat. Or, if one wants to cheat and use the forked version that supports it, you can set it to automatic mode and not even man the station. BTW, if you were smart enough to have run FT4 (and from what i saw only stations on 20m were smart enough to do that), you could potentially have made ~120-180 Qs per hour with FT4. As far as it being no different than CW or SSB -- SSB on a packed band is extremely difficult, even with the best of radios and QRM-busting techniques, not to mention the fact that SSB requires a much better SNR to reliably work a station. SSB actually requires some verbal human interaction, which is nice. CW requires more human interfaction than FT8 even though it's not a verbal mode. And it requires a better SNR to make a CW Q than it does to make an FT8 Q (I think CW and FT4 are about the same as far as SNR requirements).
FT8 station manned 24/7 by 2-3 people? What was that cadre doing for the 23+ hours that they weren't required to touch the mouse?
A lot more brain power goes into working CW or SSB versus FT4/8.
And, perhaps more people were running D-stations since Covid, but a large number of people have always run D-stations during FD for as long as I can remember. The only difference was they couldn't get points for working other D-stations. I imagine the rules will eventually revert back, and I won't bark about it. I'll still run 1D if the only other option is not running Field Day at all. You have to remember that 1D stations do serve at least one purpose -- and that is to provide many many more possibilties for contacts for those stations that are out in the field, running emergency power, etc. So it seems to me your only justifiable beef is that [currently] D-stations can get points for working other D-stations. And I would say that I'd work FD as a D-station even if I didn't get any points, if D was the only option I had.