Widescreen laptops were a phase, but they're rapidly falling out of fashion.

Being able to see more text (webpages, news articles), and longer lists (email inbox, code) is more important to more people than having a laptop that can watch movies. Split-screening on a laptop is rough no matter the dimensions. In the best case scenario you have a wide laptop and you see two panes, but a miniscule amount of rows on each pane.

Squarish laptops have been a breath of fresh air for me.