It's probably not possible in the current universe of the web, at least not without significant attention spent solely on this issue. In general a larger social network has more value if it can help you find people who share each of your interests, e.g. there is a subreddit for all things. There will always be a group of people who are drawn to new tech, but it needs to somehow actually solve a real problem that the old website didn't for most people to try it more than once.

New platforms do solve the "oh no I've been deplatformed from Reddit" problem for... people who've been deplatformed from Reddit, so certainly it has real value for them. If Reddit swings the moderation hammer too hard, that could be certainly become a draw, but as it stands Reddit has actually banned very few communities, considering.

Getting people to use a new website in any significant numbers is really hard, and there aren't that many examples of communities that have managed it in the time the internet has been alive. It's impressive that any have managed to stay relevant for more than a couple years.