It wasn't just luck. It was Jim Keller.
https://en.wikipedia.org/wiki/Jim_Keller_%28engineer%29
Intel did this with P4 "netburst" architecture. They hit a frequency wall that made thier new deeply pipelined CPU worthless. This is when AMD caught up last time with the athlon series.
Intel actually went back to the design of the Pentium III!! With higher IPC, a few upgrades lifted from the P4, and new processes, it gave birth to the Core series.
The Intel processors we have today still share more design history with the P3 than the P4. And since then, Intel has focused on IPC over clock speed.
The crazy part was AMD making the same mistake years later with Bulldozer. Makes me wonder if the remedy was the same... Go back and update the Athlon cores.
The ancient Athlon/P3 IPC is amazingly good compared to today's chips if you scale them by clock speed and core count. Perhaps half, which is impressive for the age of the chip. All these bugs affecting over a decade of CPU design tells us these chips share a lot of the same logic, if not entire blocks unchanged for more than a decade.
I mean at the time the only thing on the minds of consumers was those GHz. So the only way to stay in the market was to hunt those GHz even if it meant some long term pain. After hitting the 3GHz/4GHz frequency walls consumers began to realise that processors are distinguished by more than frequency (obviously the lay person still doesn't quite understand but they're more likely to buy based on i7 > i5 than 3Ghz > 2.5Ghz these days).
No, AMD dispelled that long before Bulldozer, and even Intel had abandoned the GHz game years ago with the Core lineup.
You're thinking late 90s, Bulldozer happened in 2011. People got over the GHz mindset in the early-mid 2000s when the market told 'em we're now going to increase core count instead, and before that when Athlon labeled CPUs like 1800+ (it's not 1.8GHz but it's as fast as one!).
Instead, ended up going i7-875K -> i5-3570K -> Ryzen 1600 -> Ryzen 3700X (probably, this year). So like, I'm glad to see AMD back in the game, but Bulldozer was pretty rough.
https://patents.google.com/patent/US3728692
https://patents.google.com/patent/US3771138
https://scalibq.wordpress.com/2012/02/14/the-myth-of-cmt-clu...
Not sure if SMT parents would fall under that, but it was my impression that AMD was relatively unconstrained wrt Intel patents due to this agreement.
I would say that only the Instruction set is cross licensed, implementation techniques and hardware interfaces aren't (AMD CPUs shall not be compatible with Intel sockets, for example). Intel's SMT is known as hyper-threading, the patent has expired too but the name "hyper-threading" is still copyright protected and the property of Intel.