PHP

All of those things done in the enterprise avoid and fix issues that are specific to the enterprise and that freelancer making websites and running WP instances usually doesn't need to worry about. While they can indeed get CI/CD and a more complex stack the advantages for them don't outweigh the costs of not having them. In the enterprise is the other way around, if you don't have those solutions the costs are much bigger.

All of the things in the first quoted sentence can be and are being done with PHP.

Yes, but the other way around can't be said. Node/Python/Java aren't friendly when it comes to stacking thousands of websites on the same server because you'll be required to run a single process for each website. Node and friends aren't friendly of a non-CI/CD deployment process because while you can upload your changes using FTP you'll still to at least go into the sever and restart node for that website... or compile the code if you're using Java/TS. This is the important part here, while you can run PHP on a more decent and complex stack it's run model doesn't actively make it hard or impossible to run in a much simpler and cost-optimized way for half of the internet.