When people increase their font size/zoom they generally don't want that - what you're describing is the default zoom on phones, etc which is different from increasing the page text size, and you'll note is typically about increasing undersized ui components rather than simply reading text.

When people are in a browser and expanding the content they want the content reflowed - having to scroll to read the width of a line is super obnoxious, and makes reading text much harder. This is made even more frustrating when you recall that a lot of time the reason for zooming is to make things easier to read.

There are very few times where the correct response to "increase the zoom" is simply an affine transform of the rendered content, from both a usability standpoint or from user intent.