I don't see it as a response to vulnerabilities, it's just new flavours of market segmentation. They have flagship CPU with HT enabled after all.

The i9 is their "performance at any cost, even security" chip. It's for people who want/need the absolute fastest chip and damn the torpedoes. It's so far past the optimal point on the price/performance curve that nobody sensible will be buying it unless they have a very specific need.

I'm no fan of the i9 series at all, but if you have SIMD-heavy workloads (especially anything you're willing to port to AVX-512), those CPUs actually make a lot of sense price/performance wise. It's a fairly specific niche, but not necessarily a tiny one.

It would be suicide to market it in this way. They actually made some security hardware improvements and highlight it. Sure, you could disable hyperthreading and I agree that it might be beneficial for side-channel attack protection, but it's not like Intel is officially accepts that as a valid option. At least I didn't see anything like that.

I think that's mostly a market segmentation measure given the timing, though in a sense you're right since it does protect consumers. They do have SMT enabled on most laptop processors, too. I worry that they'll have a hard time getting all they can out of the full width of Haswell and later chips without SMT.