Very unlikely that they'll abandon this.
They been developing SteamOS for years, and with Microsoft looking to push everything through their store, having Linux as a backup is going to be incredibly important to their business.
The Steam Deck itself is very aggressively priced, especially in the current market. Getting users to buy into the device will encourage community development and more widespread adoption.
Even if you ignore the base use case, it's a great piece of kit for the price. It can play games locally, stream from other services (cloud or network), run all sorts of emulators if you're into retro gaming.