I don't think it is very likely I'll be able to build my own mobile phone to replace Apple, who have banned Parler. Network effects and natural monopolies are real things.
Competition and organizing individuals is also a real thing, arguably there are ~74 million Americans who voted for Trump - which is arguably a large enough market size to cater a product to, which is exactly what Parler has done under the guise of a "free speech" app - which it's not: