Very interesting article! IMHO, the term “avant-garde” is relative to the moment in which the recording or performance was made.
As stated earlier, even Satchmo was avant-garde in his day. By comparing an artist’s work in the context of what was popular at the time, we can clearly define who was forging into new ground, who the pioneers were.
To say that someone had to have followed an avant-garde artist to make the leader avant-garde, assumes that one can only be avant-garde in a historical context which doesn’t make sense to me.
Jazz, by definition, is an artist’s musical interpretation of their emotional response to the moment. If that interpretation takes that artist to a place where no other artist has gone before then, in that moment, they are avant-garde.
Once the direction becomes accepted and others take a similar path then future interpretations can no longer be considered avant-garde, even when done by the originating artist. As Joe Strummer once said “if you’ve been playing for years, then we’ve already heard your song.”
This is not to say that once an artist discovers their sound that they become redundant. There are thousands of tributaries to go down and we as fans love to be taken along for the ride.