The nice thing about Lemmy is that it doesn’t have celibrities and NBA players.

If you are starting with something that is completely subjective, how do you expect to get any meaningful discussion? You might not care about these things. It doesn't mean that this is not important to others.

Also, it's not just about the celebrities and NBA players. It's about the conversation surrounding these different interests.

…eternal September . It would be guaranteed to happen.

It happened on Reddit many years ago, and because of the long tail it simply didn't matter. Just stay from the (relative) popular subs and things work quite well, as long as they are some minimal critical mass. If you are the type that insists in participating in tiring and pointless discussions about politics, then yeah you are going to have a bad time.

marketers are gonna do the same thing they did to reddit.

Conjecture, that's not a certainty. In an open network, it's a lot easier to design and implement systems where you can actually verify who is behind an account. Or to implement a system that filters content from anyone who is not part of your web of trust. Or to do like spam filters that run content analysis before even hitting your inbox. You can not implement these things on closed networks because it would destroy their KPIs, but we don't care about that here.

I’d argue Lemmy isn’t the end solution,

Of course it isn't, but it's the best we have at the moment. If we keep waiting for some ideal solution before working to get people out of the closed systems, it will never happen. Worse still, if we don't get more people, we will hit a local maxima and never innovate. This is already happening on Mastodon.

where no government or organization can control, regulate, and most importantly one that cannot be manipulated for gain of a nation state or corporation.

Here we agree, 100%.