While I enjoy my free gitlab.com account, I would prefer to use a version of Gitlab that is 100% open-source. This in order to not feel trapped the day they are bought by a bigger actor. I hope they will allow such an option.
Worth a look, perhaps.
Gitea had a lot more pull requests merged and issues opened than Gogs, so it seems to me they're the more active of the two. (See for yourself: go to both Github repositories, hit 'insights' and check the past month.) Gitea was apparently forked because they wanted more community driven development rather than by one person.
Of course, it's not a direct replacement, since they don't have free, centralized service like GitHub/Lab does. But, it's 100% open source and you can easily host it on a potato.
Not particularly reassuring since acquisitions of companies after they IPO happen all the time.
"I want a hosted service which is free-libre and free-beer, and don't want the provider to charge or be acquired by a company, and don't want to do anything other than consume their service."
How exactly is that a sustainable model?
As you've mentioned, hosting costs time, which is money. It also costs bandwidth and storage. That gets quite expensive when you're at the scale Gitlab is currently at.
Though I will say that this can be a sneaky business model. Users might not realize some of the features they depend on in the gitlab.com version isn't from the community edition.