It's not so easy. There are concentrated tech players. There's decentralized systems but they aren't there yet in terms of usability for millions of people to just log on and use seamlessly like they do w/ Reddit. It may get there eventually, but its nowhere close to being available.

And then you have different layers of protocol that are all more or less centralized. AWS, gcp, Azure isn't going to host illegal or risky content. And even if you get around that, you'll have to contend w/ the ISPs that can just block arbitrarily if they so choose.

Yes, you can get around all those, but not on the scale to make a meaningful impact and the barriers will deter all but the most fervent supporters, and they likely wouldn't have enough money or influence to cause the havoc they're causing today.