Personally, I wouldn’t include Proton in the costs of the Steam Machine. The Deck already is benefiting from it immensely, and I would consider it to be a cost of expanding into Linux gaming in general - especially with the Lenovo handheld and other devices starting to jump on the bandwagon as Microsoft continues to take repeated dumps on their userbase. Its R&D costs are being won back by the market % Steam takes on any games bought and played in Linux, which means that it can benefit from that continued revenue stream rather than the one-off hardware sale.

The hardware has to break even. The software already has.