Not what they are know for:

Okay, I suspect I'm reaching for it here, but suppose the world knew John Lennon only as "a victim of an assassin". If you look for information about him, all you would find about him is the date of death, the location, the assassin, the assassin's punishment, etc. Nothing about what he did prior to the bullet.

Now image the same thing about a composer. You want to hear music by him, but what do you get?

Take poor old Vincenzo Bellini! I noticed that someone checked on his broadcasts on the 8 major FM classical music stations I monitor. I looked too and discovered that his most popular piece is the Oboe Concerto in E flat. So old Mr. Bellini is an oboe composer. Great! Now I do seem to remember that he wrote something called "Norma". And "La Sonnambla". And "il Puritani" and "il Pirati". They must be small pieces for woodwinds or something. Were he still alive, I suspect he would be shut himself into a closet and say "I give up! My music isn't appreciated in this silly century!"

Opera isn't an art form on the commercial FM radio stations anymore -- they take too long.