[dale_glass]

A huge amount of it is going to graphics. A 4K screen is ~31 MB just for the framebuffer. In comparison, 640x480x16 colors is 150K of memory.

Windows 95 also didn't do things the modern way. It didn't keep an image of every application's windows in RAM. It kept track of what covered up what, and then asked applications to redraw themselves when needed.

Another huge amount is going to features like internationalization. Unicode is a beast that takes a good amount of code to implement, and Arial Unicode is a ~20 MB TTF file.

Modern luxuries like being able to tweet in Japanese are quite expensive.