What you did there to make your argument hold any water whatsoever was change the contention from "bassist," which is all inclusive, to the much more narrowly inclusive "departed/deceased bassist."
You don't see that as a whole lot smaller pool of bassists? You may as well have made it, "You'd be hard pressed to find bassists who were more important to Jane's Addiction and Metallica than Eric Avery and Cliff Burton."
Even there, Jason Newsted at least has an argument. The guy was a part of the band far longer than Burton, he performed on more albums and tours, and he was Metallica's bassist when they were at the peak of their success.
I know, I know...semantics.
