Actually that was exactly my point, you managed to separate identity and content by using your own instance. But for average user this will be pretty hard.
It's a cultural issue, not a technical one. When Mastodon started to take off, one of differentiating factors was about the sort of people they wanted to attract. It's very easy to market to a tribe and appeal to their identity, so it started to stick.
One of my goals with communick is to get rid of this idea, actually. I try to make the point that an instance does not say anything about who you are or who you should follow.
A lot of people can put themselves onto the Fediverse with little more than a WordPress site and an ActivityPub plugin. You're right though, it goes beyond an average user's technical capability to do so at the moment.
Perhaps Automattic (the current owner of Tumblr) can shoehorn the ActivityPub protocol into Tumblr and find a way to market that system to your average Joe.
