We're on the same page I believe. My main point is that wrestling can no longer provide a full time income and thus is not a full time job for 99% of the indy wrestlers out there. They can't devote entire days to only wrestling nor are they gaining hundreds of matches each year in experience. The devotion is still there for some, but its at best a part-time job for the masses rather than a full blown profession as it was for the territory wrestler of the past.
A present day wrestler with 5 years of experience has the equivalent of a wrestler with 1 year in during the territory era. It would take 20 years for the current indy wrestler to amass the experience that a territory wrestler gained in 5. Consider the frequency of being in the ring and the simplicity of styles back then (less moves, slower pace) and the amount of what you had to learn was much less and the rate at which you learned it was 4-5 times faster. This is why vets from that era are smooth and polished.
It could be done today, but its hardly an opportunity for most. Try to think of an indy show you could get booked on for every day of this week. Very few feds run weekdays. Sometimes a wrestler works for a fed that runs in two different areas, but they are running the same date, so you lose an extra booking due to choosing one over the other. In the territory era this wasn't a concern. Steady bookings were the regular and seldom did a territory disappear overnight as indy feds do today.
Schools and seminars can make up for this lack of experience, you can work on mechanics, but there's only so much you can do without being in front of a crowd, mainly character development and having a feel for psychology have to be done in front a live audience.