Was that his question? Or was his question if they are overlooked because they deserve to be or not?
I'd rather add up all the commenters in here who know who they are.
I just don't believe that anyone's individual relationship with a band is necessarily reflective of any greater pattern or reasoning, unless you have some data.
Being "big enough" also isn't a measurement of greatness to me.
Offering a personal anecdote about your lack of familiarity only makes the point that you might not be the best person to offer a conclusion on how great they are, not the other way around. It just seemed like a flawed basis for why they should be docked credit. A lot of the greatest and most influential artists aren't the most mainstream or recognized.
If somebody asked if Guided By Voices was the best to ever do it, that would just be another thing prompting me to give them another shot. There are acts like them who are greatly respected by people whose opinions I greatly respect, but I've never gotten into. With GBV specifically, they have a million albums and the "classic" releases that I've tried didn’t immediately connect. Part of that probably has to do with the fact that I was "trying" and things often need to click organically.
One example of that is of Montreal. I wasn't getting it at first and one day it clicked. They didn't suddenly get better just because I felt different about them.
If you ask me, Grateful Dead are "the best to ever do it," but there was a time a looong time ago when I'd rather be listening to Soundgarden.
The best GBV comparison is probably KGATLW, because they have such a vast catalog and range that it can be difficult to step into it. Right now, I feel like Gizz is one of the best doing it, but I didn't know that initially. I was just lumping them in with the Oh Sees scene.
Another thing that affects perspectives of greatness is when you hear an influential act long after you've heard all the acts they've influenced. Ironically, they can come across as less original, when the opposite is true.
There was a time in the 90s where I'm pretty sure that I was mixing up the name of Shudder To Think with Guided By Voices. That's just me being a fucking weirdo; I don't feel that's fair reflection on Bob Pollard.
If someone thinks GBV is the best to ever do it, I feel like I just have to accept that they might be correct and I just don't know it yet.
Edit: I should add that I respect you and your opinions on this forum. I'm not trying to be a dick; I just enjoy analyzing and discussing this sort of stuff.