people can already start staking eth.
the forks already exist. they just have not merged/'detonated' (where the PoW version ends).
so dont expect some massive spike of buys after the merge. instead expect the merge/stake to already get 'priced in' now and until merge
also before the merge, the PoW is going to get increasingly difficult. and yes new eth ASICs are just released meaning PoW eth will get more expensive.
this is not a situation of expecting a 10x 100x ATH due to it. but instead the GPU miners to just drop out and leave a smaller pool of miners over all where those miners are just a few lingering ASIC miners trying to snag some PoW fork coin before it merges.
so again expect the eth price to have already 'priced' in any changes before the merge happens. and then expect the after merge/'detonation' to then go straight to PoS cost/value vs speculation game
as for bitcoin
there are new gen asics releasing this year. the 140thash-300thash units. and there are many large farms buying in bulk. so expect hashtrates to go up, difficulty to go up and thus costs to go up. where by those with the most efficient set up wont sell as cheap. those with more expensive set ups that cant mine profitably would rather put money into just buying coin while cheap. and thus uplift the price.
Eth is heading in a downward cost/speculative direction over the next year
btc is heading in an upward cost/speculative direction over the next year
this is not financial advice. its just simply looking at obvious details of the mining situation and its impact on peoples price points