"Essentially nobody has ever heard of Minds/Gab/Dlive/Bitchute/, so the censorship has a very real effect on the proliferation of ideas."
Evidence for this conclusion? There are a lot of fundamental ideas people have never heard of or can't place that are not necessarily deliberately censored. A few that come to mind: President Pro Tempore, Posse Comitatus, the Magna Carta, and the Bill of Rights.
Then there are erroneous fundamental ideas that are actively being promoted, like the "constitutional wall of separation between church and state in the USA" (which is believed to mean that religion is legally banned from influencing anything in the public square), and the notion that democracy can only survive if everyone can cast a vote with minimal effort (no effort at all is even better) regardless of their level of knowledge about the candidates, the issues, or civics.
Ironically, the campaign to end "fake news" lost steam very quickly once it became clear that the more progressive media rather frequently disseminated "fake news" themselves.
Now, I am not saying that censorship has no effect. I am, however, positing that media bias, ignorance, and personal bias and interest (or lack thereof) plays a far greater role than the current suppression of certain channels.