If one buys a Radeon RX 6800 card this week when they are at a discount somewhere, the price will be $700/card including the system components. The profit after 9¢/kWh will be $1.80/day after accounting for a 2-3%/month diff growth and assuming a crab market for ETH. If PoS happens on November 1st, one makes $320 of profit after pool/software fees. There is no way the price of the equipment can drop below $380/card even after PoS. In the U.S., the depreciation is tax-deductible. So it's very likely one makes a net profit.