Yeah, it really does seem like a fundamental difference in how AMD and Intel designed their processors. Researchers have found Intel processors allowing speculation to bypass hardware protection all over the place, and they just haven't found an AMD equivalent. Not only that, AMD have looked into this themselves and released an entire whitepaper explaining why this isn't possible: https://www.amd.com/system/files/documents/security-whitepap... (With, interestingly, one exception. Apparently AMD CPUs allow speculative execution to ignore x86 segmentation. It's just that no-one cares because that's not used anymore. I'm not sure there have even been any mainstream OSes that used that for process isolation.)

This is particularly bad for Intel because most of the SMT-based exploits can pretty much only be mitigated by disabling SMT entirely and taking such a substantial performance hit that they've been trying desperately to convince people not to.

In this particular area though, it works both ways. Intel has so many researchers and resources, they are able to pursue tons of speculative execution / CPU doing something you wouldn't imagine it normally does experiments, and many of these find their way into their CPUs. A company with less resources might have less vulnerabilities of this nature simply because they don't have the resources to focus on that stuff in the first place. Just a theory.

I'm not exactly sure the monoculture argument is valid for Windows vs. Linux though; Linux still dominated server usage while Windows was attacked more often, despite the fact that you could potentially reap a much greater reward infecting a server. Unix-based OSs were just inherently more secure for the most part.

Or the bet is more subtle, that buyers are willing to eat the risk in exchange for higher perf, letting Intel still hold the title of higher performing chip and market that.