But automatically replacing a valid word with a less-common valid word that makes less sense in the context is not something predictive text should do.

You are presuming it was an automatic replacement. Some still type entire words via a thing called a keyboard, on a computer, others manually pick words to finish, from suggestions, not automatically.

Beyond that, google searches are not indicative of current usage, in SMS/messages, emails, etc. Google search spans all webpages, and many text pre-web too.

Yes, the comment I replied to with the numbers says "No room for auto-correct?". Autocorrect is the topic of this subthread.