I'd definitely call him way bigger at this point. Popularity I don't pretend is the same as most iconic. That I leave to Spongebob and Mickey Mouse bar none. The rest are just a slight bit below among the bigger icons, but very respectably notable. Of course, this is also due to how things have changed in the years. This also deals with merchandise, exposure, etc. Spongebob picked up years ago to outbeat them. Before then, yeah, I'd call them bigger. But now? It's hard to actually find them constantly be talked about or have an actual show. They never actually hit Mickey Mouse level either, though no denying they got close. That's the only thing Spongebob really has. He's as iconic as the Mouse is right now. The other two just aren't as close.
Coming first doesn't make you bigger. Otherwise Steve, one of the biggest gaming icons, would be outshone by hundreds of characters. That is definitely not the case, as he's one of the few to constantly be on par with the original pillar three, Pac-Man, Mario, and Sonic. Nobody else even comes close to being as known.
It's YMMV, but things change in time.
Most popular =/= most iconic. That means they like him more. That doesn't mean he's more known in comparison. These are completely different things. Popularity relates to iconicness, but is definitely not the sole determining factor. There's more to it than that. See above.
I'll repeat it's YMMV, but I still consider as of this day, Mouse and Squarepants the most iconic now.