I’m not disagreeing with you. You’re saying that the fediverse produces badly designed and branded services that mirror existing apps with massive user bases, that won’t be great until a lot of users migrate over. None of that is wrong! It’s why Lemmy is a mess that constantly breaks, and Reddit is still way more useful, even if most people here hate it.
It’s just that most Lemmy users care enough about decentralisation to ignore those product downsides, in the hope that they it can be overcome over time. With a messaging product, that’s even easier. You can just install it and wait until other users join - network effects are ’much more limited than with eg Lemmy.