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.
https://www.techpowerup.com/344578/leaks-predict-usd-5000-rt...
Which makes sense: the latency is determined by the underlying storage technology and the way to access that storage, which the same for both.
RAM manufacturers are switching lines over from DDR to make HBM.