Question if nowadays gpu and nvme directly talk to CPU then how come chipset doesn't support pcie 4?

[howdy.techy]

I am trying to learn about computer hardware, I learnt that modern cpu skips chipset and directly communicates to gpu and ssd. But then again there are few motherboard which supports ryzen 3rd gen cpus but do not have pcie 4. While this is not in the case of b550. So my question is if gpu and ssd directly communicates to cpu then why support for pcie 4 from chipset matters or how exactly stuff on motherboard works with each other?

I am certainly not obsessed with pcie 4, just want to understand basics of computer hardware so that I can be confident enough while building next system for myself and friends.

 

[SamMaster]

It has something to do with the traces that lead to the NVME and PCIE 16x slots. They need to be good enough for the PCIE4 speeds and power delivery else there will be problems. That is also one of the reasons AMD stated that they prevented MOBO manufacturers to enable PCIE4 on the graphics slot on 400 series chipsets. Such a thing wasn't needed going from version 2 to 3.

Edit: specified chipset