It depends, if you're automating business processes (honestly probably where the money is), then you'll need a really comprehensive set of evals and moniotoring to ensure stuff doesn't break if/when you change providers.
If you have none of that, then switching will be very expensive (but it was ever thus).
Unless your self-hosting open weight models, you need this even if you don't change providers, since you have no control of what's on the other side of the API.
I'm thinking of stuff that would typically be outsourced (like compliance stuff for identity verification et al), where it's really really hard to have deterministic rules.
LLMs are definitely a step up in dealing with fuzzy inputs, and enables you to mostly automate stuff that really wasn't feasible before.
But you do need really good evals and monitoring to make this work effectively.