Comment by krapp

It's simply that platforms are more convenient. Most bloggers never got a comment that wasn't spam, but platforms make it easier to find an audience. Platforms (if they're big enough) make it easier to find content relevant to your interests than webrings or link aggregators ever did. Most people don't want to learn how to hand-code HTML and run a server just to express themselves or communicate on the web. Curation is also a plus, but framing that as "wanting censorship" is disingenuous. What people want is stability and predictability.

It also doesn't really lead to a blandification of content. The quality of content on the web now is higher than its ever been. The value gained by being able to publish nearly effortlessly to the web without being a tech nerd is outweighed by the value lost in not being able to put a skull playing a trumpet in a site header.