I remember about... 10+ years ago, almost every game that came out had a demo you could play as well. What happened to that little policy? Nowadays it seems the only way to find out what a game is like is either to look at the ridiculously funded ads or to ask someone who's already played the game. And that doesn't solve the problem I just ran into.
Last fall my computer died. I lost a lot of files, and some money replacing it, but the important thing is that my new computer is substantially more powerful. However, it's not bleeding edge powerful, and has an integrated graphics card. So I'm finding myself able to play some games that I previously was unable to. But at the same time, I'm finding that it's very hard to determine what games I can play when I have a great processor and plenty of memory, but crap for a video card.
This is where the lack of game demos comes in. If I could obtain a demo of some of the games I'm interested in playing, I could be very sure that my computer can run them or not. Instead, right now I'm stuck trying to decide whether I want to risk $60 on a game that may end up being useless to me. So what options to I have available to me? Risk buying the game, which with my limited income right now is a bad idea. Or pirate the game and test it that way, which has obvious legal and moral issues, and frankly takes a long time these days due to the gigabyte size of recent games. Or just save my money for the day when I can afford a computer that can definitely play the games I want, which is the best decision both financially and academically. Plus, there are lots of games out there I've found that don't have tough system requirements, and are way cheaper to boot.
Listening in, game industry? You just lost a customer because you can't prove your games will work for him. =P