Genuine question: why the desire for an all-in-one? What's the specific draw vs just having a Mac mini + a nice 27" 5K display?
Fair question, to be sure. And your excellent and thoughtful suggestion may be the path for me going forward. I like AIO computers as they are an easy buy. One box, does everything, and does it very, very well. No cables for the ”computer” itself, one electrical plug, known experience (my 2017 iMac is my 3rd), easy configuration, one warranty, one AppleCare charge, small desktop footprint, and lower overall cost. At a desired config for the mini, it is $1500, plus $1600 for the display so $3100 plus taxes, AppleCare X2 ($150 + $99) for another $250.
Yeah, the 24” (actually 23.5”) iMac AIO eliminates a lot of these issues but the difference in screen size is for me significant, far beyond just a 3” diagonal change. On the other hand, a well-configured one costs $2100 plus tax plus AppleCare for $170, so major savings over the mini/studio display combo. If I can learn to live with the 23.5” display, the savings will buy a lot of nice wine to help me transition more easily.
All of this is after at least another year or so with my 2017 unless it goes chips-up. Product options could be different then.