Personally, I'm still of the opinion that there wasn't a whole lot that Intel changed with respect to their CPU lineup that was influenced by AMD's performance resurgence. I can point to two products that likely never would have existed without AMD pushing Intel: The 10 core Comet lake products and Rocket Lake. I suspect that we likely wouldn't have seen 8 core 9th gen parts either. It's also possible that Kady Lake-G might not have seen the light of day without AMD pushing APU performance as much as they did, though, I believe that the timings for it required that Intel have begun work on it before details about Raven Ridge were first released.
Intel's seeming malaise in that era was largely due to continually stubbing their two with their 10nm process. They wanted to use that process to start pushing higher core counts as it allowed sufficient circuit density to allow them to produce their desired number of die per wafer with those products. Instead, they continually pushed more and more products on 14nm with higher core counts, which butchered their dpw numbers.
Everything intel was releasing was changed by zen performance.
No matter what people might say about zen1 performance and the minor issues it had, it really did disrupt the market.
Intel desktop cpus go from 4cores to 6,8,10 and so overclocked that power draw has doubled. With 8th gen intel has started releasing the K series 6months early to recover mind share and 9th gen introduced the i9 top tier branding that amd happily followed with r9.
Laptop cpus have seen a similar trend, 2/4cores for 7 generations and through to 10gen it was now 4/8cores and 5ghz.
Xeon scalable has seen the same power draw increase and the largest dies sizes have been spread through much more of the product stack, you would see various xeon gold5000 cpus with more cache than the LCC dies could support for example.
All the above would hugely increase the silicon required for products (therefore manufacture costs) and was often coupled with a reduction in asking price in the more mainstream skus.
11th gen is a red headed step child. Tigerlake H and rocketlake are probable best left forgotten although they seemed to be the end of 10nm problems and intel's internal problems. (Fab head leaving and being able to develop architecture more dynamicly)
I would argue that if skylake consumer was 8 cores at launch (4 in small laptops), even if it's low clocked, ryzen1 would have made far less impact, and there was no good reason intel withheld that. Multiple die shrinks since nehlam with very little to show for it for consumers and amd started very strong and zen2 catapulted them ahead.
Sapphire rapids and alder lake seem to be the first real bespoke responses to zen (plus four years).
Alder is ropey, as overall performance isn't that much better for the increased costs through new ddr5 platform and heat/power to get what's advertised. I do anticipate the 2+8 cpu as it's the most interesting part, desktop should have been a single sapphire chiplet for a 15core 250w golden cove monster.
Sapphire, from what has been leaked or revealed, also doesn't show that much promise, hopefully it's a decent competitor to rome and milan but too little too late too hot. Again most interesting thing about it is not performance but the chiplet design, especially how it's very similar to naples epyc cpus but with modern high speed interconnects and also how future on package memory will compare to stacked L3.