Even for a burgeoning fogey like me, it was hard to get Joan Rivers. I only knew her work AFTER she had become a pop culture curio. I first became aware of her from the voice work of Dot Matrix in Spaceballs and then in the voice impressions Tress McNeille did on Tiny Toon Adventures ("OHH, Can we talk?!"), but beyond that, she was just this crass celebrity whose allure never made sense to me.
Rivers was one of those comedians who went back to standup after her career peaked and declined, very much like Jay Leno. People forget that Leno has been doing standup regularly for decades even during his time as host of The Tonight Show, but almost nobody outside the comedy scene knows about it because he does it in clubs and it goes unrecorded. Rivers was a constant presence on the scene, but again, most of it was never recorded for standup specials or put on the internet so if you weren't there, you didn't see it.
In some ways, she was like Robin Williams: she became famous for an act that was revolutionary for its time, and built a career off that reputation for decades. But while Williams used it to mature his career into something different, Rivers kept it going long past its popularity. I guess it's hard for us now to imagine the revolutionary quality of her early work because it was so long ago and the trail she blazed is larger and wider than it was when she started it that she no longer seemed relevant to us now. The same thing happened to Richard Pryor, with the exception that Pryor's work was documented in legendary comedy specials that never left rotation.
Either way, I still appreciated that some legends never die, they just keep working, and even though I despised the kind of pop culture claptrap she touted, there was something comforting about the ubiquity and reliability of her presence in the ether.