twitter has never nor would it have ever been "a public town square"
anything owned by a private company is the literal opposite of a "public" anything.
and way more importantly, anything with a character limit of 280 characters is absolutely thoroughly inadequate to discuss the most complicated and nuanced subjects that philosophers have been wrestling with for centuries with entire tomes and libraries worth of space.
And I definitely prefer social media that support long form posts and contextual discussions instead of these weird loosely linked twitter threads.