8086 was launched in 1978[1], so the x86 architecture is quite old, spanning over 45 years. How long before enough patents expire so those who don't trust Intel or AMD can launch a competing compatible implementation?
I'm sure you're free to make an 8086 clone. Maybe even of an Athlon 64. It's just that nobody would buy it...
Even without the patent issue (I assume AVX etc. are still restricted) hardly anyone has the talent and resources to be build something even remotely competitive from scratch. Even if you do going with something from ARM and then building you own core when you're ready (like Qualcomm/Nuvia or Ampere) seems like a better idea..
