Before big tech, there were no global platforms where anyone could just speak to millions/billions of people for free (as in money).
You weren't "censored" by big tech because there was nothing much to censor. In the past, if you wanted to reach a massive audience, you had to go through the traditional news media, big book publishers, major TV stations, or the like, and they were definitely selective about who was allowed to speak.
Also, the so-called "town square" where strangers gather to discuss politics in public is largely or entirely a myth. There are of course public spaces, but what happens on Twitter is not what happens in real physical town squares. And of course there are city council and other government meetings, but they are strictly controlled by government officials, not a free-for-all free speech zone.
Traditionally there was more friction to speech. I don't even mean just that the average person doesn't have access to a national platform like CNN. Even something like mailing out fliers had non-trivial costs. It's the same reason why junk mail is generally less of an issue than email spam.
In a traditional town square, people are not anonymous and the "square" was local enough for there to be social consequences to actions. On Twitter, many of the posters are anonymous and even those who aren't often live on the other side of the country.
In my experience, and I used to run a "freedom of speech" channel back in IRC many years ago where I allowed anything as long as it wasn't illegal. These sort of measures end up restricting freedom of speech much more than enabling it. The reason is very simple, if people are allowed to say anything; then harassment becomes the norm and because a lot of the targets of these harassment are more sensitive then they end up leaving. You might think this is okay, but I tend to disagree, as I believe when people harass others out of a platform that it constitutes a form of violence.
Of course, I think this is actually a very complicated subject. And that's precisely my point on why I believe we need to have better conversations on what do we actually want. But as things stand now, this conversation is always reduced to what Elon Musk now thinks should happen. To me, this form of monarchic governance is sub-par to what is required for a platform as big as twitter.
The problems I've run in to on it is that that some channels on IRC were run by powertripping assholes, and you'd get banned for disagreeing with them or having different opinions.... even if you were perfectly polite, didn't threaten or harass anyone, etc.
Of course, you could just go somewhere else... on to another channel, another network, or off IRC entirely... the internet's a big place.
Still, the fact that some popular channels were dominated by assholes and there weren't viable alternatives to them sometimes is a problem for people wanting to participate in a large public space.
You can do exactly the same thing on IRC... and IRC had that a long time before Twitter even existed.
In many ways, these people don't really care about having a space to say things and instead they want a space to be able to say it to people who don't want to hear it. It is why they don't actually use the spaces they've created for themselves like parlor or truth social. They want to tell trans people that they are not valid, they want to tell women to stop having abortions, they want to tell black people that they're criminals, etc. They need an audience. And if you allow them to have it, what ends up happening is that these people being insulted and belittled will leave.