Why does that matter? If US vendors decides to kill the service for EU customer, they can move a webserver on a different VPS within hours. Same for git. Sure you can kill GitHub, but the git repository can be moved somewhere else within minutes.

However in both cases US vendors will suffer catastrophic trust loss for rest of the world. It would be a lose-lose situation.

If the company I work at was forced to leave AWS and put all of our engineering teams to work on this, maybe we would finish it in 6 months, being very optimistic.

If it were forced to do this immediately, it would shut down.

Not everything is a simple web server that fits in a VPS. Some systems have thousands of moving parts, and some of those parts are proprietary services that only have one provider.