Just sampling from myself at home, with my close friends, and my purchases made in the university there have been 2 Threadripper Pros, 3 Ryzen 9s, 4 Ryzen 7s, 1 Ryzen 3, 5 Core i7 (8th gen laptops) and 6 Core i5 (7th gen) systems in total in the past 5 years.
That's 2 out of 21 systems as HEDT and those are there solely because we had budget in the university to go 8 channel ECC RDIMMs for some very memory intensive workloads. If we hadn't a couple of 5950x CPUs would not have set us too far aback.
Given the phase out of DDR4 slowly beginning, TRX chipset aging somewhat, and a new big architectural refresh coming with the mainstream I can understand AMD pulling back stock to maintain what has already been sold (RMAs require a stock for a couple of years). There are also rumours that Intel might try to get back into the segment (not that I'd want any at their current state as HEDT chips are already difficult to cool quietly, but it's still a factor).