It’s not so much about filling stadiums but being able to survive long enough to get really good. If the chilli peppers are used as an example the first couple of albums were great in terms of energy and they were good musicians. They didn’t really come into their own as song writers until Blood, Sugar, Sex, Magic. The same could be said of U2 with the Joshua Tree being as breakthrough album.
Surviving to album 3 or 4 historically has been really hard. I’m not really sure it’s even possible anymore even for signed bands, which is a huge loss to music.