[TacoSteemers]

One reason is that someone else's platform means you don't have full control over presentation and discoverability.

Also, at some point in their existence each platform start to decline. People move to the next platform and lose some of their readers. A few years later the same thing happens again, and readership is reduced again.

Personally I have had a lot of fun adding random bits to my website such as small tools, some explorations on creative expression with CSS and things like that.