It's true that Valve probably won't want to lose money selling a hypothetical SteamOS console, but they make all their money through Steam, and people using SteamOS will probably buy a lot of games through Steam. The goal for them probably isn't to make money from hardware sales. It would be to jump start a market for SteamOS console-like devices made by other companies, like they're doing with the Steam Deck for handheld devices. Plus this would be mid generation, so getting PS5 level performance for a similar price wouldn't necessarily involve losing money right now, since console manufacturers haven't seemed real interested in price drops this gen.