Yes but he doesn't understand it.
Twitter is driven mostly by the media and regular personalities.
Trump brand is toxic, and so very few luminaries will contribute.
Combine that with the fact that unregulated speech online immediately results in people calling for some guy they don't like to be lynched, literally, and you have a problem.
Even Trump's allies are all on Twitter, because that's where the audience is.
If Trump were a sharing guy, he could have given America's right wing luminaries each a small stake in it, and required them to put >50% of their content there.
And then talked about it like it was 'free speech' but secretly just have slightly more lose moderators.
Paradoxically a 'free speech' platform that benefits Trump would come out of the anarcho-socialist types. A Pirate Bay type thing I think is more likely to find themselves overrun by unpleasant people, and then maybe get acquired by Trump or something.