For a lot of people pushing on 3 buttons to create a facebook page is enormously satisfying and spending any more effort is ridiculous. The open web is disappearing because of the opportunity cost.
That may be true but it's not that much more effort to create a hosted Wordpress site or to create a blog on Blogger. Arguably, those still lock you in a bit more than self-hosting Wordpress with your own domain, but the data is exportable and there is some migration effort associated with moving no matter what you do.
Actually you don't need a credit card for Blogger; it's a free Google service. And while people have beefs with Google as well, Blogger uses pretty much standard HTML if you want to export it.