And AMD just accepted $1.3Billion instead of waiting to be awarded $30+ Billion because their case was so strong.
AMD had a strong case, but you have to put everything in context. In 2009 AMD
needed to complete the Globalfoundries transaction because if ATIC pulled out there would be no one willing to put monies in there, and they would probably have gone bankrupt. They needed both the cash and the GLF deal, so for them it was a worthy compromise.
Have in mind that AMD only settled after Intel - correctly - sued them for breach of the then-current patent agreement, which didn't allow them to manufacture chip of their own fabs.
For Intel it was also worth to settle because no investigation could proceed without AMD collaboration, and because AMD wasn't their only problem. If regulators had access to the process files and they found Intel guilty of something, the liability could be worth a few times the settlement value. Independently of the verdict it would be more than a mere nuisance to have litigation on the US, Canada, Europe, Japan, Korea, etc. Have in mind that not all of the settlement value would go for AMD's war chest, a lot of it would be to regulators in the form of fines.
As I said, I don't think Intel deemed the practice illegal at the time. Aggressive, yes, but not illegal. And in the end it didn't matter what Intel did as AMD burned whatever money they had made with K7 and K8 when acquired ATI, their engineering was already in disarray bulldozing the internal controls to allow Bulldozer to proceed and they had already chosen IBM as their source for process node, all the elements of the perfect storm that happened in 2011/2012.