Quoting: mr-victory

Quoting: sarmadThe GabeCube's target audience is mostly Steam Deck owners who want to continue their gaming session on TVs with better resolution and frame rate, and those won't bother with anti-cheat because they'll mostly be running the same games that run on the Deck.

Is that the only possible audience? Such people would be satisfied no doubt however I expect buyers to play different games on the cube, F2P FPS or retail AAA games more often while on Deck the most popular game was Vampire Survivors for months with many other indies in the mix.
Perhaps DOA was a strong word, the better way to put it would be "many people would refund it". Which I believe can create a negative impression and push away potential new buyers but yeah I was pessimistic.
I'm partly this pessimistic because where I live the go-to game most people play together is EA FC (formerly FIFA), there are even "PlayStation cafes" where people meet up and play EA FC. The cafes have PS4/5 with a selection of games but typically everyone plays EA FC, which doesn't work on Linux. But the Deck is not even sold in my country sooo...

Definitely not the only audience, but I would say that's the primary audience. And yes, many people will not be satisfied as you say, but I think Valve doesn't need to satisfy everyone for this to be a success. When the PS4 was released it only had a handful of games but people still bought it. So, it depends on how Valve markets the device. They need to make it clear to customers that not every game is available for it, but on the other hand its launch library is bigger than the PS4's lifetime library and that should be a big selling point.

Too bad that FC doesn't work, but at least we have e-Football. Let's hope UFL supports Linux when it gets released on Steam though I'm not sure how good it is.