It does seem like it might, in general, be a very opportune time for GitLab (or another host) to publicly step up!
There seems to be a lot of chatter on X recently about wanting an entirely new GitHub usurper that doesn't look like GitHub at all, but in the short- to medium-term I expect this not to gain a huge amount of traction because of the sheer cultural embeddedness of git + GitHub in modern day software development.