Google, Facebook and Twitter run all the major social media channels, are immune to political repercussion, and any alternate platform either struggles to compete due to being a smaller company with less attention, or is attacked by the political/media class like GAB was.
It's not like it's a simple service or product that you can go buy a no-name brand of, it's a monopoly on a market where networking and advertisement are key. Twitter wouldn't have caught on if literally every major public figure and news outlet wasn't convinced to sign up. YouTube wouldn't have caught on if it wasn't the catchiest and earliest video hosting website.
Are you going to convince every media figure to go on your Twitter copy? Are you going to be able to create a video hosting website and have everyone awestruck by the novelty and ease of it? It's just not going to happen, and this social media stuff is more akin to a utility nowadays than a product. Or are you such an ultra-capitalist that you think Edison and Tesla's family members should be getting a cut of everyone in the world's usage of electricity?