No. This is simply not true, at least at the extreme you are suggesting.
What I have open on my quad-core 8GB RAM desktop right now: two Eclipse sessions; One emacs server, with about 20 client windows; Firefox, with 30+ tabs; 20 or so console sessions; five PDFs of documentation; an IRC client; an image viewer and a Jabber client. All of this is spread over two big monitors, with antialiased fonts, fast scrolling, lots of undo history and all sorts of good things.
The truth is that expectations have changed. Say all you want about having 1000 users on a single core, but users today are getting a much richer environment, and capabilities that we only could have dreamed of twenty years ago. This isn't waste or inefficiency, it's using what we have.
Web browsers are also far from simple. High resolution graphics, interactive sites, multiple format support, dynamic content loading, antialiased fonts and all these other things do add up. Compare that to what a user was doing on a tiny slice of a machine 20 years ago. I'd call it progress.