I discovered Mahler in college. My father ranked him as “some obscure German symphonist.” He was clueless.
I had a friend in college who would only listen to TWO composers...
Mahler
and
Frank Zappa!
But, as you said, he was relatively unknown until Bernstein “resurrected” him, so it is reasonable that I didn’t “grow up” with his music..
I love the kettle drums in the second movement.