The point I think is that as GitHub adds more and more integrations (git + issues + fork graph + CI/CI + ...) then it's not so simple to move to another service. The vertical is more convenient until you realize you're an Oracle customer all over again.
With CI, I wonder if someone could build a tool which had some sort of DSL to define your CI pipeline, and then translated that to configuration files for multiple CI providers (Travis CI, CircleCI, GitHub Actions, Jenkins, etc.) If you write all your CI pipelines in that DSL, then moving to another provider would be just telling the tool to generate output for another backend.
(One issue is that such a DSL could only provide lowest common denominator functionality... or else, suppose CI providers 1 and 2 offer feature X but 3 and 4 don't, then if you use feature X, you can switch between 1 and 2, but the tool would give an "unsupported feature" error if you tried to generate output for 3 or 4.)
Having migrated from Travis to CircleCI for most of my active projects, I’d say their models are so vastly different it’s pretty much impossible to have an AST of sort that can be translated to both except for the simplest and most well-encapsulated cases (at least not before Travis supposedly improved Docker support, by which point I was already gone).
