I don't get this comparison of Doom to webpages. Doom is a famously well-made classic video game made by an exceptional programmer. John Carmack is not making "the average webpage." Comparing Doom to "the average webpage" makes no sense; they do completely different things. Doom took you 40 minutes to download in 1993, if dial up had been faster, you can bet that Carmack would've shipped a bigger game.
Good video games give you the ability to decrease or increase graphical quality to deliver the best experience on variable hardware. As networks, hardware and browsers improve, so will the demands of "the average web page." You can try to convince people that they don't need the things that they've come to expect from the web, or you can work on finding ways to deliver better progressively enhanced websites.