I don't think it's that they couldn't, it's that they consistently choose not to. Nintendo's first party titles are arguably much stronger than those of Sony a

I don't think it's that they couldn't, it's that they consistently choose not to. Nintendo's first party titles are arguably much stronger than those of Sony and Microsoft, but Nintendo is not particularly interested in the graphical power arms race. They'd rather build something that fits in the pricing segment they've always been in, and maybe try to innovate on how people interact with the console. Their strategy makes Nintendo somewhat unattractive to AAA third party developers but they're profitable on every system sold, and they sell plenty of copies of their major franchises.