You mentioned it yourself but i believe you massively underestimate the economy of scale. Of course pixelheart wo rely on Crowdfunding can't compete there with an operation that potentially has the god like power of Saudi money in its pocket (this obviously depends on how the operation is structured, did plaion only license from SNK or did SNK pick them to do the whole thing for them)
But don't get me wrong I'm not saying this will work, you obviously have to be stupid to not worry about over promising products in the retro gaming space, but at least to me the Carts seem to be by far the most realistic part of the whole thing. The stick's being low quality, the compatibility of the console not being as promised, the HDMI sucking or the (software) options for the picture output being trash, sure. But the Carts are "simple" with less space for true variance, if you put them in a Console and they work you basically 95% there (at least as long as we aren't talking about LRG…).
*About the Saudi money, just checked plaion and they are owned by Embracer which supposedly got scorched by Saudi Money so not sure if I'm still counting on that…