Naive question but wouldn't it could as having AI write 50%+ of your code if you just use an unintelligent complete-the-line AI tool? In this case the AI is hardly doing anything intelligent, but is still getting credit for doing most of the work.

Yes there is even a small business that champions an small LLM that is trained on the language Lsp, your code base, and your recent coding history (not necessarily commit, but any time one presses ctrl + s). How it works is essentially autocomplete. This functionality is packaged as an IDE plugin: TabNine

However now they try to sell subscriptions to LLMs.

Tabnine has been in the scene since at least 2018.