Github is deeply subsidized by Azure's marketing budget and benefits from larger scale. Gitlab can't compete head-to-head; they'll have to pivot or partner soon.
GitLab is now $19 - $99. If I wanted to move my organization to GitLab it would now cost me an additional $78 per user, per month. A total nonstarter, even if I desperately hated GitHub.
I don't understand the suddenness to this maneuver by GitLab. My guess is it is driven by the CI/CD minutes, but they have really thrown out the baby with the bathwater with their pricing structure.