I also think you're possibly a bit naive about the condition and technical knowledge of the pins and owners floating around public venues/homes/sheds in the parts of the UK with lower land prices than London. Having spent some time looking for rarer old pins, and talking to owners, there are people with SS pinball machines sitting in their offices/workplaces/sheds/front rooms that they know little about, have no idea how to maintain and - in some cases - daren't switch on. I have had to give people lessons, via FaceTime, on how to do something as simple as get the backglass off.
I feel like that's a different point entirely.
You said
"generally - 80s pins tend to be the neglected step-children of collections featuring modern Sterns and B/W-era"
Older pons in the corners of rooms and offices where they were bought to look nice, probably years ago when cheap is different. I'm quite aware of it and it's a different thing entirely, different type of person who wants to own a pinball machine because of different reasons.
You could be looking at the same situation in a few decades where people have WPC games sitting in corners of rooms.