I actually think Intel HAS to offer IFS to AMD, not because they need them, but because it's a terrible look if they turn customers away for competition.
As I mentioned, I think AMD is safe, but as I think about it, possibly less safe than I initially mentioned.
Yeah, Intel probably doesn't want them, would definitely accept them if they were willing to pay same as customers. Intel own desktops and mobile, over 80%, and it's less clear if their higher performance nodes would be as attractive in servers. But, either way, yes, they'd be tossing an advantage away, which I believe currently gives them the performance crown in single-threaded performance. But, they'd look like clowns if they said, nope, only so and so can do business with us, because we compete. No way they can that. Plus, Mr. Pat has said he'd be interested in their business.
So, it really falls to AMD. And AMD might want to use them, for exactly the reasons why you say Intel shouldn't let them use their fabs. Not only would AMD have access to potentially superior nodes to TSMC in some metrics, Intel would find it less profitable to engage in price wars, as they would make money either way (more on their own stuff, but it would change the calculation as to where the most advantageous price would be). Not only that, it would keep their fabs busy, again making it less imperative to drop prices as much.
I am not suggesting it will happen, but you and I both know crazy stuff happens all the time in this world of ours (and it keeps getting crazier), and this really isn't that out of the question. I think the odds are low in the near term though, so I am with you on that.