People have been telling you what the problem with your reasoning is, you just don't want to listen.
A 17" laptop is comparatively large (and thus also heavy); a 4k screen at that size will be hard to manufacture (tiny, tiny pixels) and therefore extremely expensive. Just because you can buy large cheapish 4k desktop monitors and TVs (the only really cheap ones with TN tech and therefore very bad color accuracy and angles) doesn't make 4k laptop screens price competitive. Driving a 4k screen will be more work than any laptop could hope to manage. You'd need GPUs so big the laptop would be thick as a brick to fit the necessary cooling. Also, battery life would be counted in minutes, not hours. Also, weight. Also, price.
It's too soon, and simultaneously too late. The era of 17" laptops has passed. Just because you like them and think they're a good idea doesn't make it so.
But go ahead and tell me how I'm insulting you just by stating facts, like last time.