I think, today already its not very likely that ETH switch to POS (same as assuming that Bitcoin switch to POS).
Except that Bitcoin never said it would go POS. Maybe it's a perpetual threat to keep miners interested.
Anyways back on topic...
The VRAM size gap between the 3090 & 3080 way out of line with the cuda core count difference.
I wonder why.
Not an issue for mining but the 3090 is the only one that supports SLI but it's a 3 slot card, leaves no room in the case
for ventilation.
Ampere uses Cuda 11 and compute 8 but I don't see anything that helps mining. Significant software improvements
look unlikely.