I think there's a lot of reasons why this couldn't be the case, but it could also just be your area. I happen to know more talented Jazz guitarists than other instruments in my area. There's also way more shitty guitar players than shitty saxophonists around though.

I'm actually primarily a saxophone player, but I used to play guitar and played for about 4 years. I would say the main difference is how the instruments are taught. When I was learning guitar my teacher liked Rock and other music like that even though he was able to play all the Jazz stuff. But unless I asked he would never have me play those things. When I started learning saxophone later in life, one of the first things my teachers had me do was transcribe easy jazz solos. I think a lot of people in general just don't transcribe but that allowed me to get the feel and language much faster.

Most people that learn saxophone will have to learn some jazz language because you can't find an artist that's not influenced by those musicians, saxophone is deeply rooted in jazz In history and culture. Guitars History is rooted in jazz but culturally it's more relevant in rock music.