"Great musicians who should have been famous except...."
That's a good question but it depends on who you ask....the public or other musicians? All of the names mentioned here are outstanding. Kudos to those that recognize Steve Gadd as one of the great drummers.
Steve has been, and still is, one of the most sought after drummers. Especially for studio work. It may be harder to name people he hasn't performed with than those he has.
In his 70's now he still performs. He is a native of Rochester, NY, where I reside. Every year Rochester hosts a multi day event called the Rochester International Jazz Show. Because Gadd is a Rochester native, the tickets are almost impossible to come by. He still has the skill to play.
If anyone would like to listen to some of his early work try to find an album called Stuff. Stuff was the original band that played of the early Saturday Night Live TV shows. The album is a mix of music but maybe tuned to the more jazz taste.
Good to hear that Gadd is included in the group of fantastic drummers mentioned here.