That's the opposite of my impression of their history. Intel's approach to x86 historically has been asserting that it's basically impossible to implement a clone due to their patents, which they aggressively asserted to keep any competitors out of the market entirely if possible, and restricted to older ISA features if not possible. With the main exception of AMD, which was initially given patent licenses and tolerated in order to meet 2nd-source requirements. But even AMD they tried to strongarm out of the market later, leading to litigation where AMD eventually won a bunch of continued patent licenses only as part of the lawsuit settlement. Intel has also used patent lawsuits over the past 30 years to attempt to limit competition from Cyrix, Via, NVidia, and Transmeta, among others. Though they did lose or unfavorably settle a number of those lawsuits.
It's kind of difficult to believe this when the relevant architecture of today (x64) was developed by AMD. X86 is ancient, any patents that can't be avoided would have expired years ago.
AMD included a number of Intel ISA components like SSE2 in AMD64, which was ok for them because AMD has a patent cross-license with Intel, but means it's still a patent minefield to implement it.
No. Patents are generally valid for 20 years from the initial filing. The idea is that you get a limited term monopoly in exchange for making the details of an invention public.
Intel has engaged in some strategic patent litigation over the years, but if you look at the chart in the article, it looks like there has been a big push to get more ISA patents in the last several years.
