The reference to Transmeta looks interesting to me, because I understand it as proof that Intel is not in a strong position here. Well, if a startup was able to counter big company, one can assume Qualcom has some cards to play.
Beside, I know there was (successfull) lawsuit regarding CPU patents by MIPS years ago. Does anybody remember ?
Last, litigations referenced above was for CPU execution some code natively. How can this apply to was is, after all, kinda interpreter (hello p-code :-))
The Windows ARM x86 emulation solution is hardly new. Windows NT on Alpha had Digital's FX!32 32-bit x86 emulator. Despite Alpha having, at the time, a considerable performance advantage over x86 it still did not gain significant traction. Still ARM is a lot cheaper than Alpha ever was so it may get more significant traction.
AMD has rather liberally licensed x86-64 in the past to other companies including Transmeta and VIA Technologies. The issue with x86 has typically been Intel, who enforce their patents rather severely, they typically try to kill their competition in the crib.
As for who Intel is directing their guns at I have my suspicions. There have been a couple of recent initiatives to clone x86. One is the Chinese Loongson. Which is a MIPS CPU with hardware x86 emulation support. Another is the Russian Elbrus-4S. Which is a VLIW processor with hardware x86 emulation support. The last one, which is probably the most important, is NVIDIA's rumoured Denver CPU project. NVIDIA bought ALi Corporation a couple of years back. ALi sold a 386 compatible processor at one point. The rumours say NVIDIA basically was developing an x86 compatible processor but supposedly because of possible litigation issues (with Intel) they gave it up. I've also heard rumours of some of the large cloud vendors being interested in developing their own x86 compatible processor to use in-house (i've also heard of them being interested in ARM and RISC-V). But I don't know how reliable these rumours are.
If they sue they'll sow fear and uncertainty in the market for ARM-based Windows for several years, guaranteeing it goes nowhere.
Their patents on basic x86 functionality have long since expired, and AMD holds patents on the 64 bit x86 functionality they introduced. Intel's only patent claims (as mentioned in the quoted section) for SIMD functionality where patents haven't yet expired, i.e. SSE and AVX. It isn't clear if Intel could win a suit where software is emulating the AVX instructions, but like I said, they don't have to win, just freeze the market for years while it makes its way through court.