I don't buy this idea that the bass & equipment doesn't make a difference; it's baloney IMHO.
Chris Squire is being used as an example of a case where the kit is irrelevant, but he had a finely tuned ear and there's a video of him saying that the Rickenbacker CS tribute models sound "nothing like" (sic.) his original.
So no, the idea that the bass, amp, whatever is irrelevant to the sound is just bunkum.
Many musicians look for a sound which differentiates them; why would they do that if it made no difference whatsoever?
Of course, if the greats had chosen a different sound, then there is a high likelihood that they would still be the greats.