Mega Man's much bigger and expansive IP with hotly enduring fanbase still campaigning on the series to come back though - not to mention we got about 2 games in last 5 years (kinda? Megaman X Dive is an odd beast due it's origin...)
Not something you could say about Goemon who's pretty much had it's much smaller fanbase gather to more confined spaces as no new games have been made for the series for almost twenty years now.
It's feels pretty similar observing the general non-preference to C-List Nintendo-IPs vs flagship ones we see in Smash but with 3rd Parties - legacy's there definitely but the general reach in videogaming pop culture today isn't due obscurity. It's why Sakurai's passed on Takamaru and Ayumi Tachibana before, something I feel can be said about rest of obscure reps that he put as Assists often.