At least so far the RTX 5090 seems to be available and at the same price it’s been at for the past six months (around $3000). I’m not sure when you’d see GPUs affected by the RAM price increases.
I'm pretty sure GPUs have their own RAM installed that is usually higher spec than the motherboard RAM.
There's been rumblings.
https://www.techpowerup.com/344578/leaks-predict-usd-5000-rt...