>>717649238 (OP)Because it's not viable.
Sony crushed SEGA during Saturn/PlayStation due to the fact that Sony have their own factories manufacturing chips. SEGA and Nintendo had to pay other companies to get chip sets.
This lead to the N64 hardware being so expensive that Nintendo had to omit an optical reader and go for cartridges to save costs and put the N64 in the same price range as the PlayStation.
And then Microsoft came along.
Simply put, going for the most powerful hardware is very expensive, and Sony and Microsoft can always do it cheaper and better than Nintendo.