You can change size of elements in Emacs too. Hint: 99% of what you're looking at is text, so it boils down to changing font sizes. Emacs already has commands for zooming content in a frame, which work like +/-/0 in a web browser.
Thanks for clarifying something I failed to explain. The relative ease with which I can change the size of most of the elements in Emacs is the reason I didn't switch to, for example, Textmate or to Sublime Text when those editors appeared on my radar.
Emacs, terminal emulators, Plan 9 port, Chrome and apps based on Electron are the only apps on the Mac I have been able to figure out how to change the size of most of the elements of.
"most of": The size of the menu-bar and pop-up menus is fixed in all of those apps when they are running on a Mac, but Apple made the text in them large and legible enough to suit me.
Setting the scaling to a fractional value in System Preferences doesn't count because the result is too blurry. I never obtained a monitor with a horizontal resolution of at least 2560, which is the minimum needed to set the scaling to 2 in System Preferences.
