Students just don't use all the sites. Sites may be inconvenient at times, but there are enough. Most of the time there are enough. At peak times, weekday evenings and Sundays, there is a wait. There are enough.
People can find a way to get to a computer.
On weekends and early evenings there are no lines. The lines are during the day. Yes, there are enough computers. Most of the time there is at least one lab open. If there is a line, it is only about 15 minutes long.