It's the design and marketing of the product. Game consoles are designed and marketed to play games. General-purpose computing platforms are designed and market

It's the design and marketing of the product. Game consoles are designed and marketed to play games. General-purpose computing platforms are designed and marketed to do almost anything (including but definitely not exclusively to play games). Apple says "There's an app for that", while console developers don't say that, nor should they, because it would be false marketing. If game consoles were marketed and sold as general-purpose computing platforms, then consumers would be very disappointed with them, because they make crappy general-purpose computing platforms. If iPhone or Mac were marketed and sold as game consoles, consumers would be similarly disappointed with them.