a) Release a Steam Deck successor (Steam Deck 2, 3, 4 or whatever)
b) Have the Steam "Box" have the same hardware as the Deck of the same generation, but with a higher TDP (and better cooling), maybe better storage options and a bundled controller
c) Break into a broader customer base by bringing the Deck and the "Box" to other retailers and stores (Amazon would be a huge one, but also big national brick and mortar franchises outside the US)
d) Maybe do some advertising??? Most gamers don't even know about the existence of the Steam Deck yet
e) Bundle games or Steam gift cards with the console (at least for offline stores)

Any objections?