You are saying it's mostly about sheer numbers out in consumer hands? Naw, I don't really buy into that, there are a fair number of model 70's out there...is there a cottage industry for model 70 trigger replacements? Extractors and businesses up grading them? In my experience, most of the time people replace bbls on a mod 70 is for changing cartridge. There are some great 700 bbls, but there must be a lot of dogs too, every major maker has a 700 pre-fit. Entire bolt assy for 700, 300 bucks, if they had any in stock. Then you need a bolt knob too. The 700 was designed to be built with a minimum of machine tool operations, manufactured easily, sold cheaply to the mass market...it's up to the consumer to make it perform. IMO.
I give up a fair amount of accuracy, add some weight, but for practical hunting, reliability, make mine Mauser. Every major maker has had to pay Mauser patent infringement fines, Springfield '03, Winchester 54/70, Enfield P14, 1917. Imitation is the sincerest form of flattery.
"Perform"....I had an early 80's 700 adl in 30 06 that would shoot 6-7 shots into 1 ragged hole @ 100 yds bone stock, plenty of performance in my book!
