> The first downside to "Anyone can build anything" is that "anyone" means anyone, and the people to whom decentralized systems are the most attractive are the ones who are banned from other systems, often for good reasons.
This is an often overlooked point from the user perspective. Decentralization sounds great when a website censors content you didn't want it to censor, but most users don't realize just how much unwanted spam and abuse content gets quietly removed from public platforms on a daily basis. The sheer volume of spam or even just angry/abusive users on public platforms these days is hard to describe if you haven't been on the spam/abuse prevention side of a popular website.
Worse, the most abusive users tend to be the most persistent. They can become very good at gaming things like IP blocks, reputation systems, or voting systems. The best users can quickly get frustrated with even small levels of abuse and leave a platform.
Decentralization seems to work well for cases where individuals are privately interacting with other users they already know. It seems much more difficult to solve the problem of public forum websites where anyone can contribute content. That's a dream come true for spammers and abusers. I'm interested to see how this space evolves as these platforms try different solutions.