Is it really harder than with lemmy? In mastodon, basically:

Subscribed = home feed
Local = local
Global = all

If you join a big enough instance, the local and global timeline will have plenty of posts. Possibly, what you're looking for is 'algorithms' that recommend juicy things (for you). But this is usually something favoured by for-profit sites, which want to push certain things and not others to increase the time people spend on the app and therefore maximize their ad-based profit.

I really don’t get how people don’t understand that for mass adoption you need as little fucking friction as possible.

A big factor is that most fediverse instances aren't really looking for mass-adoption. Since these things are usually run by volunteers that have to pay for hosting with their own money or donations, and not a for-profit corporation, there's no real incentive to advertise and get as many people as possible to a single instance. The ideal is that smaller instances federate together, there's no centralized "fediverse" interest that wants to get them all.

Ideally, we'd want a web that is less corporate and more federated, but if no one is currently able to give the time and money to pursue this more aggressively, it will not happen. That's not really gatekeeping. In theory you could fork mastodon, improve it to make it easier for people, market it and sustain the hosting and moderation costs. But when you complain about how nobody is doing it already and call it gatekeeping, it's not really fair.

A lot of the fediverse is also composed of 'beta' software that will probably improve with time, but these improvements are based on people that work on it on their free time.

Yes, there's an inherent difficulty in competing with big corporations, but this is an open problem so far. Yes, if meta or some for-profit company join the fediverse and use their large budgets to make them very attractive for mass-consumption, it will grab most of the users. This is the whole embrace, extend, extinguish problem that has supported other closed system that dominate the market. How to fix that is a larger problem.