I'd pay for public repos (I don't need private repos, all of my code is free software). In fact, I would _donate_ $30/mo to GitLab if I used their services enough (unfortunately the projects I maintain live on GitHub and I don't have the authority to change that).
I have no problem donating to free software (I donate $10/mo to Neovim, $10 to SirCmpwn (sway), and other bits and bobs here and there -- as well as donating my time to openSUSE, runC and the OCI). The only condition is that I have to use it enough that I feel that they are owed some money to make the software even better.
I hear you. GitLab self hosted is fast but GitLab.com is too slow. From Monday we're having a daily 50 minute call to coordinate our efforts around https://gitlab.com/gitlab-org/gitaly We'll try to reduce IOPS and make GitLab.com fast.
Gitlab is superior in every possible way than Github except for it's speed.