Why browsers are bloated

https://github.com/WebKit/webkit/blob/master/Source/WebCore/platform/Scrollbar.cpp
https://github.com/WebKit/webkit/blob/master/Source/WebCore/platform/win/ScrollbarThemeWin.cpp
Let's reinvent the fucking scrollbar, which every goddamn platform with a UI already has, and make it behave subtly different from the native one!

Right-click a native scrollbar in some other app:
- Scroll Here
- Top
- Bottom
- Page Up
- Page Down
- Scroll Up
- Scroll Down

Right-click a scrollbar in Chrome:
- Back
- Forward
- Reload
- Save As...
...

Right-click a scrollbar in Firefox and Opera:
Absolutely fucking nothing happens!

What the fuck!? How did these terminally retarded idiots get involved in creating one of the most important pieces of software to the average user?

Some limits to consider:

255 attributes per simple selector ([a1=v1][a2=v2]...[a255=v255])
255 simple selectors per selector (#s1 + .s2 > .s3 #s4 ... s255)
4G selectors in total (theoretical limit, actually limited by memory available)

These limits should be sufficient for basically all the CSS out there... and if it's not, then fuck you. No page should ever have anywhere near that much CSS, and if you do you'll probably crash other browsers and deserve to have your page displayed unstyled.