I think that doesn't actually prove anything beyond the name of the character being more memorable.

Baby Yoda show vs Mandelorian, sure.

Even at the height of popularity, it was never the "Bart" show, it was always the Simpsons.

The specials are largely how people are introduced to Peanuts today, are from shows that are named:

* A Charlie Brown Christmas

* It's the Great Pumpkin, Charlie Brown

I think the takeaway is that the character name is more memorable because Charlie Brown is more recognizable due to being better marketed, today.