Who is the current audience for jazz? - other musicians, as has been said. Jazz, at least in the US, is less consumed than classical music and ranks the lowest among genres. In its home country! - sad.
I say this often on this forum: jazz - insofar as it exists as a culture/sub-culture, style, philosophy, attitude, etc. - eschews (derides?) commercial success. I lay this at the feet of the beboppers. Not from a stylistic perspective but rather from an attitudinal one. Bebop was developed "after hours" by cats looking for musical avenues with greater individual expression and technical virtuosity. And, there was a well-documented vein of thought among the bebop progenitors that bebop be so virtuosic and harmonically complex that White musicians couldn't steal it and thus commercialize it to White audiences (make $$$). There was an element of resentment, quite understandably, toward the commercial success of "White bands" among some Black musicians of the era (i.e., White bands playing Black music to White [wealthy] audiences at White-only clubs while Black musicians were not afforded similar opportunities for commercial success). Obviously this is wrapped-up in racial segregation, economic disparity, and other not-flattering characteristics of racial relations in the US in the early/mid-20th century.
So, for me, it's not that bebop ruined the party due to the style, it's that bebop was created and developed without consideration for commercial success (i.e., jazz became an "art music"). Other, non-racial factors, were at play, too: namely WWII (conscription) and the '42 - '44 instrumental recording band. By the time swing bands recovered from the war and the industry recovered from the ban, Americans had moved-on and swing was viewed by young people as "pre-war" music (recall how cataclysmic an event WWII was!). Not to say that America had moved on to bebop - although it did achieve some commercial success - but Americans had certainly moved on to other sounds: "race music" (RnB), country blues, small-group jazz, cool jazz, gospel, etc. And from a commercial perspective, why would clubs pay to bring-in a massive swing band when a hot 7-8 piece group could also pack the place? Then it was only a few short years (1953) that Bill Haley would hit the charts with rock 'n' roll/rockabilly. Elvis followed the next year.
Swing didn't die completely immediately after WWII. Basie, for example, briefly disbanded (2-3 years) in the early-'50s before creating the "Second Testament" band and the great records that followed w/ Hefti, Quincy Jones, etc. By the '60s, however, swing was "Vegas music" (i.e., your parents' [or grandparents'!] music). Obviously there are still some "ghost bands" operating today, but they subsist by playing 300 dates per year.
In sum: once swing faded from American consciousness there just wasn't an emphasis among those in the genre on commercial acceptance - by design. And, due to that, jazz in its entirety largely faded from American consciousness by 1965 (arguably sooner, ~1960). There are notable exceptions: Louis outsells the Beatles with "Hello, Dolly!", Stan Getz wins a Grammy for Getz/Gilberto, the Tijuana Brass tops the chart a few times, Chuck Mangione in '70s, Kenny G, and some others - but none of that was considered the "hippest" jazz happening at the time. To the contrary, most of it was "throwback" or "old" jazz.