That's the beauty of the free markets. You can always compete. The problem is that alternative social networks such as Parler don't have wide enough audience as

That's the beauty of the free markets. You can always compete. The problem is that alternative social networks such as Parler don't have wide enough audience as Twitter. But that's also an effect of the free market. If there were enough people who value having access to the kind of content which can be found on Parler then it would be more popular. Twitter is simply catering to the majority of consumers. The market interest for networks like Parler, Gab, Voat, Thedonald.win, etc. is simply too small for any of them to succeed. Their audience is also too narrow, it's just politics and almost no discussion about anything else. If a ton of people would suddenly move to Parler it would mean the majority wants it and Twitter would respond by enabling the kind of content they are banning now.