Sure RAM is meant to be used, but not when the browser just consumes it forever, until it begins grinding to a halt. What could a browser POSSIBLY be doing with 4-500MB of RAM PER TAB? It's a huge problem, and extensions like The Great Suspender should not have to even exist.
Except we're not running an entire operating system in each tab. Everything starts fine, and then quickly consumes memory. How about we just stay fine? I've got entire operating systems running with less resources in VirtualBox.