Not so.
Swans and WCE did it once in their eras, same with Pies.
They have done it twice in increasing impressiveness.
That perspective - the idea that teams that win two flags are *always* better than teams that win one - only makes sense if you operate on the self-evidently absurd assumption that every era is of footy equally high standard and every premiership winner has to face equally difficult teams to win.
As far as I'm concerned teams that win one premiership in a high standard era, with high standard rivals, is clearly better than a team that win two flags in a weak era with weak direct rivals. Collingwood 2010 for example was a miles better side than either of the Richmond 2017/19 sides, and history should judge them as such. Huge gulf on quality.