Userbenchmark is useless, it can barely compare between Intel microarchs. Best it can do is """help""" compare two processors from the same family.
The last big microarch jump for intel was Skylake (6th gen) and then 7, 8, 9 and some of 10th gen (but not all, but they needed "10th gen" for marketing reasons) are just incremental improvemnts over it. So Skylake was about a 15-20% increase in performance (real) but took a few shortcuts (Meltdown and Spectre). From then on, you had a 5-10% performance improvement per generation (let's round it at 7%). That's not bad per se, but it was done out of comfort. The "cursed" 10nm node which never came is also part of the reason why Intel stalled, they insisted on "tick-tock" and were unwilling (or unable?) to deliver a new microarch over 14nm+++, the super refined node (and the extra refinement allowed them to pull the clock higher on each new gen, now alowing those sweet close-to and with this new weird turbo [that seems more marketing than substance] surpass the 5Ghz barrier).
And that's how you come to Intel's situation on 2020: no 10nm node, no real new microarch in the last 5 years.
Edit:
As for why we never saw something like this... I think we never had a situation before where one of the competitors had such an advantage (the microarchs before Zen on AMDs part were bad, and that hit them hard for a long time) that they could pull this duckish moves for so long. For a long time, Intel chose not to improve their offering, because they were so far ahead of competition and they could keep milking the Whatever-Lake microarch family. They'd blame on the difficulty of extracting more IPC, Moores Law coming to an end (or not coming to an end, depending on what marketing was trying to sell).
In the end it came to AMD+TSMC offering superb processors for Intel to slash the prices in half, and then still being crushed performance wise, in desktop, server and now mobile too. And all Intel has to show is AVX512, which after having it gatekeeped for years in the server market, they've released on consumer processors - but hey, nobody's using it because there was no support!