Almost nothing of IE is in the 'IE' folder
Whereas everything of Chrome and Firefox is in their respective folders.
All the guts of IE are in various 'core' Windows libraries. This goes back to when they were trying to avoid being done for abusing their monopoly in the OS market to extend into other markets, a tactic that pretty much worked.
(IEFRAME.DLL in System32 is 0.010 GB, which alone takes IE up to 0.023 GB before you even look for any of the other ones.)