… but Rocket Lake with Cypress Cove uArch is the first significant uArch change since Sandy Bridge a decade ago. Skylake was a significant enough iteration of the previous Sandy Bridge derivatives to call it a new uArch but at the same time it re-used so much of the existing uArch that it is hard to call truly new
Calling something a "new architecture" always ends up as a semantic discussion, and strictly speaking I don't think Intel has made a "new" desktop architecture since P6 or something (even that is disputable). There is nearly always something carried over from the previous one, even parts of the dead-end Netburst(Pentium 4) was carried over to Core.
I prefer to talk about major vs. minor architectural changes, and the sequence for Intel after Core would be:
Core -> Nehalem -> Sandy Bridge -> Haswell -> Skylake -> Sunny Cove -> Golden Cove (upcoming)
All of these have offered major improvements. Even the often overlooked Haswell was a good improvement over Sandy Bridge, especially in heavier applications. In dense math, even single ints and floats, it scales better than the IPC (which is an average) would lead you to expect. In single algorithms, it's not uncommon to see performance >60-80% faster in Skylake vs. Sandy Bridge, and that's without any AVX or any special instructions.
And don't forget that sometimes an architecture lies the groundwork, before it becomes more useful and refined later. E.g. AVX(1) introduced in Sandy Bridge wasn't that useful or performant at all, then Haswell extended this and offered massive improvements.
… and at 7 years old when the Spec-Ex vulnerabilities went mainstream, it became very apparent that Skylake was not a new architecture but an evolved Sandy Bridge.
That's a very flawed assumption.
Just because products have the same design flaws, doesn't make them the same. For most of the vulnerabilities found in Intel, very similar problems were found in all other modern microarchitectures, even though the share none of the same designs. (The same can be said when independent web browsers or SSL implementations have the "same" bugs without sharing code.)
What they do share however, is assumptions. When engineers are building comparable products using the same assumptions, they are destined to do similar mistakes. Most of the high level research for CPUs are done by academics, and is ultimately used by all the CPU designers. If there are flaws in this research, these flaws can end up in designs for years or decades before someone discovers it. That's why questioning assumptions and critical thinking is crucial, but are seemingly forgotten in the sciences today.
