Like gab.ai and Parler? LOL.

I don't think it's going to play out that way.

The problem with Facebook and Twitter is that everybody is on Facebook and Twitter. Some alternative comes up (let's call it Foo) that lets Trump speak freely. How many Facebook people are going to move to Foo to hear Trump? (Remember that the value of a social network is proportional to the square of the number of people there, and nobody's on Foo yet.) Sure, some will go, and Foo becomes a nest of die-hard Trump supporters. And over there, they get worse, more hardened in their position. They also don't get many new converts, because if you're not already a hard-core Trump supporter, why on earth would you go to Foo?

Is that better or worse than the current situation? I think it's better, because it shuts down the recruitment pipeline.

The popular vote for the presidential election was 51% to 47%. There are more than enough disaffected conservatives to allow Foo to not just survive but even become a roaring success, particularly if boosted with endorsements from leaders in that party. To believe that deplatforming people "shuts down the recruitment pipeline" for a political movement with such broad popularity is wishful thinking.