It's been working out fine for the Steam Deck. Sure, you can install Windows and/or any other storefront, but you won't have the console-like experience that Valve's own software provides.
It's trivially easy to install pirated games on the Deck, without any cracking or modification of the system. You never have to make a single Steam purchase after buying the Deck, but Valve's betting that you will. And they're right, that's enough. Most people don't go redoing or even tweaking the software stack on their hardware, they just stick with what comes out of the box.
