Why I don't hear bass drums on Jazz LPs?

A small further observation - in rock and pop music, the pulse of the music is set by the combination of bass drum, snare and hi hat, whereas in jazz the ride cymbal is the dominant pulse setter.

@OP, you will hear the bass drum in jazz recordings, just don't expect it to be there all the time or on two and four.

BTW Bruce Gary was the drummer in the Knack - an absolutely outstanding and underrated drummer. Check out Africa (not the Toto Jeff Porcaro song) on the Round Trip album.

@bdp24 

Amazing knowledge of the drum, thank you for sharing. And your musical experience is fascinating. Here I was loving music as a teen and then moved on to a business professional life which in the end allowed me to get back into my passion, music. But it seems as you have lived in music your entire life.  And you survived it! For what it's worth, some of my favorite drummers are Christian Vander of Magma, Ginger Baker and more recently Gavin Harrison.

If you go back to the 40s big bands, you’ll hear Gene Krupa’s or Buddy Rich’s bass drum driving the whole band. 

Vintage jazz recordings are not particularly noted for their bass reproduction.  Even the string bass is poorly recorded in a lot of them.  For one thing, those recordings are fairly heavily compressed, dynamically speaking.  They were meant to be played on consoles, not Theils. ;-)  In addition, the bass drum wasn't heavily featured in small-group settings like Hawkins or Webster dates.  A lot of jazz musicians didn't like drummers who dropped a lot of "bombs" and called attention to themselves.  The drummer was supposed to stay in the background.  If you listen to Buddy Rich or Gene Krupa in the 50's Verve albums, they're fairly restrained unless called upon to "let loose" on occasion.  

In the late 70's, as a student, I used to frequent the Buena Vista Lounge at Disneyworld.  The house drummer was quite loud and aggressive, and a lot of visiting jazz veterans didn't like him, calling him "Boom Boom."

Listen first live to jazz in a club or theatre or a concert than asked the same question. I think you never asked again.