alt Hacker NewsThe whole "UIs got smaller because the aspect ratio got more rectangular" thing never really made sense to me because 786 > 600. The screens got bigger in both dimensions, regardless of them getting bigger in one more than they got bigger in the other.
Pixels aren't physical space. The number of square inches remained similar.
A wider aspect ratio means that a horizontal line takes up a larger percentage of the overall screen and is more costly.