An IDE is not just a text editor. There is a nontrivial amount of configuration that goes in a build system, and the IDE takes care of some of it. Having to ditch the IDE often means having to manually reconfigure a good chunk of the build system, as well as tracking down the exact version of build tools the IDE was shipping with in a particular release.
And this just for IDEs. Intellij also ship a lot of tools (youtrack etc) which may or may not be replaceable without significant data loss.
Note that YouTrack and other tools are not moving to subscription licensing, only the IDEs are.
Pretty much everyone has their project set up to be able to build via an external tool for CI anyway. I'm really not seeing the lock-in argument here, except that moving back to Eclipse would be painful for a lot of people. But I don't see why you would go through that pain now if you're currently happy with what you get from JetBrains for the money that you're paying.
And this just for IDEs. Intellij also ship a lot of tools (youtrack etc) which may or may not be replaceable without significant data loss.