[Dr. Jacoby]

… basically everything that is not created in the moment of playing (besides the obviously existing base composition).

Most “real” jazz is not 100% “created in the moment of playing.” Jazz musicians play arrangements. (See Art Tatum.) Even much free jazz will use some sort of a roadmap as a jumping off point. (See Anthony Braxton.) Improvisation in jazz usually occurs within existing frameworks.

Just jazz chords itself does not make music jazz.

Much more than chords. Rhythm, groove, feel, alternating between swing 8ths and straight 8ths, accents, etc.

That’s why some jazz purists will not consider a written solo (like Williams’ noted above) as real jazz…

Then they are also discounting much postwar jazz, including Ellington’s extended compositions, third stream compositions, etc.