Exactly this. Computing isn't x86 exclusive anymore, in fact the "average" consumer who isn't an enthusiast is much much more likely to buy an ARM SOC as their primary computing device. There are still a few users and enthusiasts like us left for desktop (desktops are my thing, I love them... I hate that they're in decline so it pains me to say that..), but unfortunately new consumers just aren't buying desktops as their first computer or gateway computing device. Therefore wintel isn't a monopoly in the computing world. This is a stark contrast to 10 years ago where everyone bought a new wintel PC for their primary computing device. Heck, everyone in my extended family bought a PC for their computing needs 10-15 years ago. Now they all buy tablets. You see where i'm going with this? x86 isn't the dominant force anymore, therefore not a monopoly. AMD being acquired by intel would change that very little.
Also as mentioned, there's a strong likelihood of AMD going out of business without some help. The rumors could very well be completely untrue (actually it seems likely untrue), but if they are true it would be good for AMD IMO. Perhaps it's just a method to spur trading as IDC mentioned, who knows.