The way Macgirvin has summarised this else where is that mastodon’s lead dev wasn’t mature and competent enough to make good engineering decisions for the fediverse at large. That his platform became the dominant one is likely earned but also likely attributable to the fact that Gargron (masto BDFL) was young and keen enough to go all in at the right time…
Which means, at this stage, dominance and immature mistakes and flaws are likely to go together (sounds familiar huh). Which means that for the fediverse to grow it has to go beyond mastodon. It just won’t happen until masto is ousted as the clear dominant platform. And in reality, I don’t see that happening any time soon the way things are going.