Damn, that's a good point. I'll preface it by saying I appreciate the Blues but don't really listen to it--Jazz is my go to music to listen to. I think people will continue to listen to it and appreciate it the way Classical music has had (and I'm sure will continue to have) a fervent following for centuries.
I think the Blues' has had a greater influence on music listened to more people. Everything from Rock to Bluegrass to Country owes its roots to the Blues.
As a pure form, I think Jazz is more important a music performed and loved by more people than the Blues but as a foundational/influential tradition, the Blues is more important.
Hard question to answer.