Thanks for sharing. I understand what you mean for sure. Your last sentence is spot on no doubt. Booker wrote about this subject. You may find some of it here in his quotes that sort of approach the subject gently.
https://jazzprofiles.blogspot.com/2013/09/booker-little-1938-1961.html#:~:text=“I%20can't%20think%20in,must%2C%20how%20to%20resolve%20them.
This is such a rich topic to explore overall., I wish we could sit down and have strong coffee and rap. I love it.
To kick off (and of course this is obvious) ...
Louis Armstrong Hot Fives and Sevens - one of, if not the first time, true improvisation was documented and extended in that limited time of a jazz 78. He went off, and thus, his legendary bandmates were encouraged to do the same. Bewildering and revelatory (even if Jellyroll Morton was doing the same.) The days of King Oliver's strict arrangements and tyrannical control over his bands was over. It was the King or the highway (as Louis found out for himself!)
Personally, I believe this manifested itself later in Lester Young's solos on the Kansas City Seven sides, where he would lay down lines that were basically all improvised within the melody. Hypnotizing.
Of course that leads to Bird's Dial sides to Monk's early BN's, and on. Sorry for stating the obvious here.
In the end you are totally correct. It is generational when the "new thing" appears.
Where shall we have coffee :)