Interesting question - so interesting that it made me want to log on here for the first time in like seven months, lol.

Matt has already said a lot of what I would have wanted to say, so there's that. Though, it sounds like you're talking purely in the context of technical communities, especially given your example. And because you mentioned it, I kinda want to comment on how technical projects become popular anyway, reflecting on stuff I've observed with other projects, and owing somewhat loosely to personal experience.

So, how do projects like Magisk become so popular? Assuming the creator behind it wasn't already well-known, well, it's kind of simple.

The main thing is - you've already mentioned it - there was demand for it. People would see it, they'd be like "hey, that's actually really cool and useful!". They then tell their friends who may also be in need of something like it, the cycle continues, etc. Since demand is needed, it usually has to be something that most people have never seen before, or something better at least.

That cycle usually doesn't start from nothing though. At first, it'll spring from self advertisement. If you have a small following already, you might talk about it there. You might create a forum post for it somewhere trying to showcase what it does and why it's so great. If you see someone on Reddit asking about something, and you know that your project can solve their problem, then you talk about it there, etc.

If you manage to gain some traction, from there, the cycle sort of just keeps going. Hell, if you're lucky and it's not too niche, people with a large follower base see it, they like it, and they tell their audience about it. Typically, you see this in the form of YouTube tutorials or showcases and stuff.

Then of course, once your project has been established as being popular and respected, then you can start talking about fame (popularity is a better term IMO).

A lot of it depends on the target audience of your project, how large it is, how easy to use it is, how useful it actually is, and there's elements of luck of course.

If you are starting work on a project of your own, you should never have to worry about any of these things. It sort of just happens, if it does at all.