Nintendo can make sure their handheld has affordable hardware yet can play all their AAA games as they were meant to. Steam Deck can't ever have that luxury. Some Steam Deck makers will make expensive ones that can play most of them, some will make cheaper ones that aren't made for those games at all.
This is very difficult to explain to the casual buyer (think parents buying as a present for their kids).
You have strange opinions regarding kids. Compare the price to a mobile phone.
/father of three