I think the expectation is mostly that GPUs don't necessarily increase IPC. Consider that IPC here is not really instructions per clock for the whole device but instructions per clock per core. So suddenly what you call a core matters. On CPUs a prime way to increase IPC is to add execution units, but on GPUs it is often easier to just go to more cores so the IPC for a given core doesn't increase that much.IPC comparison between 40CU: https://www.computerbase.de/2021-03/amd-radeon-rdna2-rdna-gcn-ipc-cu-vergleich/
Somehow, RDNA2 is behind RDNA1 in most cases.
It's just immature drivers?
Changes that could increase performance (I'd rather not use instructions because with all the fixed function hardware it is a really bad indicator) per clock are:
1) New accelerators like raytracing. The problem with measuring this is that nobody seems to support the software feature you'd before hardware support.
2) Non shader features like variable rate shading or mesh shading
3) Improvements in the memory hierarchy
4) Maybe some improvements in say branch prediction.
I don't think AMD talked about any things like 4, and looks like 3 has been traded off against a smaller bus with so that is a gain some lose some situation. Leaves 1 and 2 which are kinda in a situation like AVX512 tends to be on the CPU side: if you have programs that make use of it it is great, otherwise kinda useless.
Of course sometimes there is a real performance per clock per core increase. RDNA1 was actually a great example because AMD was able to remove a lot of the bottlenecks to keep the shader units busy.