If twitter had a problem with the split between mega-accounts & all the rest having so few followers that you get no interactions... Mastodon's opt-in profile discovery policies are going to make that 10x worse.
The people that put effort into being found will get lots of followers and the people that don't will become "follow only" accounts.
And what is more normal is for people to not follow hardly any one and there will be new users who just have dead accounts.