Eh, xeon 2690 was released 2012q1 at 8 cores, 2690v4 was 2016q1 at 14 cores. Same suggested customer price. Clock speed dropped a bit, but IPC was way up (AES-NI had a big throughput increase among other things). IIRC, desktop core counts were pretty stagnant, but a Haswell/Broadwell desktop chip at the same corecount and similar clocks was much faster than a Ivy Bridge/Sandy Bridge.

During 2012-2016 AMD was firmly in the Bulldozer disaster.

In 2017, Zen1 came out, and Intel's tick/tock mostly stopped. Zen1 was better than Bulldozer, but not better than Intel. Zen2 in 2019 was the big moment, and Intel hadn't done much. I recall an interview where the AMD person (might have been Jim Keller) said they had been targetting Zen2 to be competitive with what they thought Intel would have when it came out. Since Intel was in their pipeline bubble, Zen2 was a big win.