What would it take for you to move away from Github?
Let's be honest, the majority here probably has a github account. Some of us are happy as a clam and wouldn't switch no matter what happened, but there are some who would and haven't yet. Why?
pull request model? Every one of the competing services
CI/CD system based on YAML definitions? Most every competitor.
static site hosting? Most competitors
protected branches? Most competitors
I'm not saying there isn't vendor lock-in, but I am saying it likely isn't the features of GitHub that are limiting that. Third party integrations will follow wherever the foot traffic goes.