With just 10 pieces of 3090s you are already at 1GH on the Ethash algorithm, why aren't people doing this instead of having so many GPUs around, taking so much space and having to use more risers and more motherboard, why are people not going this way?.
Hmm sorry why should i buy a gpu for 2000€ or now for 1800€? Because it has over 100mh? Sorry this heat problems with GDDR6x, the efficiency is also not the best.
I prefer RX5700 - consumes around 120w and do up to 55mh - for me the better W/MH ratio
No many bought AMD Vega7 3 years ago - they do 100mh at 200w for 700€ (at the release), much better than the RTX 3090.
I also have a couple of AMD 6600xt running at 0 - 25% fan and temp is around 55°C, so nearly noiseless and really no heat. Different person prefer different thinks, and not all have the money to start with GPU´s for 2000€.
When i see the market - if you want a gpu that make over 2$ a day you must pay around 600€ - in 2017 we bought GPU´s for 200€ with the same reward. The same thing happens with asic - an s9 cost me 2000€ in 2017 and it make up to 20€ daily. Now miners cost 10000$ and make the same money.