If an Eastern European gamer making, say, $400 a month, buys a $1000 PC, he will probably be doing so through a small loan paid over 2 years with an interest rate of at least 20%. Which means that he will be paying at first, some 50$ out of his monthly income in the first year.
Now, it's not unreasonable to suppose that this gamer will spend $300 a month in various expenses, including rent, food, phone, gas, electricity, water and transportation. Now, how does this gamer play games on his $1000 PC? He pirates them.
Now, I said Eastern European, but I could have said South American, Southeast Asian, or Southern European. These are huge markets and games simply aren't priced to be sold there at all.