I also want my browser to be fast and responsive, but the current trend goes in the other direction. How on Earth can you occupy GBs of memory? How much time does it even take to download a gigabyte of data?
No, it's the internal representation of the markup, and the program state of all of the javascript programs a page might incorporate, that takes up a lot of memory.
Well, judging by the graphs in the linked article this is clearly something that every browser vendor experiences. I imagine that the trade off in speedy page rendering is having a lot of memory intensive data structures.
It's prolly more complicated than we give them credit for.
I've never liked the griping about memory use - if you're not swapping out to disk then you're perfectly fine. I'm much more concerned with having firefox occupying a whole core if I leave it unattended with too many js intensive tabs open.