Why does the developer console open on the bottom, constraining your vertical space? Because there is such a dearth of horizontal space that that it would be uncomfortable to do otherwise. The reason things keep eating up vertical space is because that's the only space that's not at a premium.
Actually, the developer console has defaulted to the right side on new profiles for a while now.
Most monitors are 16:9 because that aspect ratio fits certain popular entertainment media content that people consume, and a significant usage of general purpose computers is consuming that content (and, also, a significant use outside of general purpose computers of displays is for consuming that content, which effects the economics of producing panels.)
That doesn't necessarily reflect the relative value of horizontal vs. vertical space in other applications.
I remember using a Vista machine for a short while and immediately looking for a way to disable it (also because it kept asking for widgets to put in there, if I am not mistaken; but that is besides the point).
Screens are more wide then tall and for me my vertical space is more valuable. Every line that holds only static info (address bar, open tabs) is not strictly needed at all times, so I want them either to popup (like the menu bar in full screen view) or at least move to the sides ('cheaper' space).
I am somewhat surprised this is not more common opinion.