> If a competitor puts out a better model than yours, people can switch to theirs by updating a few lines of code.

This may become increasingly the case as models get smarter, but it’s often not the case right now. It’s more likely to be a few lines of code, a bunch of testing, and then a bunch of prompt tweaking iterations. Even within a vendor and model name, it’s a good idea to lock to a specific version so that you don’t wake up to a bunch of surprise breakages when the next version has different quirks.