I think the popularity of Magnavox depened a lot on the local dealer. I see a pretty good number of them around here, and remember at least two Magnavox dealers in my area, 12 & Harper & 11 and Ryan-ish (both gone now). The dealer at 12 & Harper was also a repair shop. They sold used sets, perhaps as a way to make up for only having $$$ new Maggies.
The only old sets I ever saw at estate sales in Sun City were Magnavoxs. I also noticed the the local Maganvox dealer had huges ads in any old Sun City calenders, phone books, etc. Business must have been good.
I remember a white cabinet tube set playing, with a good picture at a Estate Sale around 2003. Right off the bat, I was kinda concerned about that old set playing pointlessly at the sale. I would have bought it, but somebody beat me to it... I hope it was a TV collector, but shudder to think it might have been a future fish-tank
Not much interest in "old" in Phoenix.