A large amount of things won't work with the best of software optimizations. You won't be able to decode 4k videos on 20 year old consumer hardware. You won't b

A large amount of things won't work with the best of software optimizations. You won't be able to decode 4k videos on 20 year old consumer hardware. You won't be able to run games with today's 3D graphics on an N64, no matter how much you're improving the rendering engine. We absolutely do need faster hardware for a whole lot of things, especially multimedia.