Bought it, tried it, don't really like it because:
1. The controls are moved around, and old muscle memory is unhappy when using it.
2. They use a lot of battery power because to just look through them to spot subjects they have to be on, and they don't have or don't like carrying around batteries.
3. They found that aside from being mirrorless and a bit smaller and lighter, the pictures are not spectacularly better than their DSLR bodies, so not really worth it to them to relearn the controls and stock up on batteries.
4. Furthermore, they need to buy new lenses because using them with the old lenses + adapter wipes out most of the smaller/lighter thing. And those new lenses are $$$$.

I have 1 full frame DSLR (5Div), 3 crop sensor DSLRs (7Dii, 80D, 90D) with a pile of EF/EF-s lenses and an R7 with 1 RF lens and one RF-s lenses plus adapter and 1.4x extender. I am making the effort to learn the new camera, but actually my new Sony RX10iv is getting a lot of my time as it is so handy to take just-in-case. If I plan on a trip to do the birds at the Riverwalk then I will haul out the R7 with 100-400 + extender or the DSLR of choice with the Tamron 150-600 G2 and extenders. And at 77 last month, I may consider hiring a lineman from the high school team to act as "gun bearer". A couple of bucks, a stop at the fast food joint and maybe some free photography lessons (I taught basic photography a bit on the side when I was still teaching history, geography and government.) and maybe the loan of a camera now and then should get me a good strong one fairly cheap. Besides, he can double as my bodyguard to prevent some #$@&% from mugging me for my wallet and that expensive photo gear.