This entire legal issue is stemming from one technicality: Are these new spinoffs truly in accordance with the agreement. I'm sure AMD thought of this beforehand, and because they went through with it, they obviously thought they'd win if a disagreement cropped up. If it really is the way Intel says it is (it's probably somewhere in between the two), then it could be interesting to see the implications of this - the extent of which I suspect none of us really knows.
However, AMD cannot just retaliate by withdrawing, say, x86-64. They signed a separate contract for that, and if there's no breach there, it still holds. They could opt to muck things up when it comes time to extend that agreement, but until there's a breach there, AMD can't use something like that as leverage.
If AMD could just pull the plug on something else, Intel wouldn't be this belligerent. They're not stupid, devious maybe, but not stupid.