Kind of doubtful, unless they can also bring the mainstream over with them.
That's the rub: Whenever a new platform starts up, marketing itself as the "free speech alternative" to some big, mainstream platform, what always ends up happening is the new platform's user base consists entirely of people who got kicked off the mainstream platform--leading to all the toxicity and problems noted in this sub-thread. You need to be more than a place where the cast-offs from mainstream sites hang out. You need to bring the mainstream to your platform too.