I also suspect this, but I use it without the network permission*, so only the local AI is active, and I don't see any problem.

Having billions of users training the AI 24/7 is a huge resource, but the quality improvement should be marginal at this point since the current quality is already very good; I'm surprised that someone else cannot emulate it, even if with less data.

* I keep the permission enabled only few minutes after the installation to download the additional languages and any possible update.