Computers cost $$$$$$.
And, especially if you're in high school where computers are usually provided in class and the most processor-taxing homework you get is an essay, a high-end computer is more or less an expensive toy.
What's high end? For $AU780 you get a 14", 1GB graphics, 4GB ram, 500GB laptop. Cheap. As technology expands rapidly, things get cheaper. You can probably pick up a 512MB graphics / 4GB ram pc for less than that now. Don't know where you guys are, though, but still.....
If by highend you mean a powerful beast of a desktop, well for $25,000 I believe you can get the most environmental killing piece of electronics known to man.
Still, it doesn't solve the original problem.
Unless you can (ironically enough) get a better graphics game like Oblivion running, than you're looking at alt-tabbing a lot.