A bad game can be patched into something a little less bad. The core game will remain, unless you're patching the entire concept and gameplay, which doesn't really happen. Yes you could rewrite the whole thing but that happens so rarely that it doesn't really apply, and certainly not enough to justify calling Miyamoto's quote out of date.
I'm not so sure about your last paragraph either, but I'll bow to your superior knowledge on that one. I'm just surprised in 20 years Playstation doesn't have much of an identity, character wise at least, apart from the brand name itself.