CSPs making own hardware still needs hardware companies, they reduce the Nvidia tax but still need the likes of TSMC, Broadcom, micron/sk hynix, Marvell, the truth semi-companies. CSPs will not have the patents, IPs and talent to replace any of them.

Also, not sure how well CSPs inference stack is compared with vllm + nvidia. A lot of open weight models uses MoE, making the inference stack more complex.