If games need to be multiplatform, what advantage does a super powerful box have besides graphics? It won't use that power to create new game play experiences, because else those games would not run on other platforms.
It reminds me of NEO GEO. It was priced way beyond the 'normal' console prices at the time, but at least had arcade quality exclusives for it. A new Super Box won't have that. The NEO GEO still failed commercially.