Because Nvidia’s supply-limited cards are almost impossible to buy otherwise.

Nvidia is bringing back a tool for getting its new GPUs into the hands of gamers—weeks after the GPUs went on sale. The release at the end of January saw many stores running out of GeForce RTX 5090s and 5080s quickly,

Remember the 'Verified Priority Access' program from the RTX 4000 launch? It's back for US buyers, though you'll need to have an NVIDIA account.