When you say "history" you are talking about an incredibly narrow slice of time when recorded music was just starting really. Before that, if you listened to music at all it was live. And in that case it was either folk, or something popular at home, for most people religious on Sundays, or classical for the tiny elite minority. None of that actually depended on selling anything to the masses. Popular and folk "sold" itself, and classical was commisioned or produeced for and by the rich. It's almost not worth comparing any of it to the history of recorded music UNTIL you had LPs because that's when real music became truly available to the masses for the first time.
Certainly singles played a big part of radio play and culture throughout the 40's and beyond, but so many other things were different then too. Look at Ray Charles, who had numerous hits. Sure, but he also had years to build and devlop his work. He had a label that supported and belived in him. They were not looking to cash in and out in 1-5 years and then move on. That is what musicians face today. A short-term investment with quick earnings and blockbuster singles.
Many of the "greats" that people point to of the 60s-70's started out very slowly. Look at the first albums of the Rolling Stones or Beatles. Good stuff in there for sure, but not the huge acheivemnts of later years. They all had years to grow, learn and perfect their work.
That is what is REALLY missing today, not raw talent. It's rare that greatness doesn't come with as much or more practice and growth as talent.
Yes you quite correct with everything you so clearly stated.
For a similar take on the subject of popular music throughout history check out Richard Thompson's take on the concept: