Regarding chrome, browsers are basically operating systems nowadays. A standards compliant HTML5 parser is at the bare minimum millions of lines of code. Same for the renderer and Javascript engine.
That's true. I'm not saying a browser solves a small and simple problem. But on the other hand Chrome takes much more RAM than the operating system (including desktop environment).
Even after closing all tabs, since tabs (and extensions) are basically programs in this operating system.
Even after closing all tabs, since tabs (and extensions) are basically programs in this operating system.