You can see a future where a user types in "plan a vacation for me" and ChatGPT coordinates everything from there. Those sorts of users aren't going to switch because model X is 10% cheaper or better.
I could easily see OpenAI become irrelevant in 2 years if they stumble at all and don’t keep up with the other frontier models.
Google's quality has gone to shit, but internet searching is still "googling", both in verbiage and in the actual service people use. It's not an impenetrable moat, but OpenAI would have to stumble pretty hard to lose all of that edge.
That said I think it is pretty easy to make a case that these would-be differentiators are either currently underwhelming or completely unproven (as in the case of hardware).
Having a good model is one thing, being able to serve that model at good speeds and match demand is another. See Anthropic ~6months ago. Or Moonshot, they've already suspended subscriptions to their coding plans, because they can't meet demand.