[judge2020]

Maybe i'm misunderstanding you, but if a 3080 costs 700, and it makes $8 a day, with an electricity cost of $0.10/kWH or roughly $0.60 a day (which is possible in many cities, and this can be improved by overclocking the memory and underclocking the core), it's making at least $200 a month. That's an ROI of three and a half months at worst, and then it can be flipped on the used market to nearly recoup that initial investment (or recoup more if supply issues are still a thing at the time).