The wait timeout is the maximum time the PostScript interpreter will wait for input before aborting. The timeout interval begins when the interpreter finishes executing everything it has received so far and starts waiting for the host to send it more data. If this timeout expires and no more data arrives, a timeout occurs.
In particular, a compute-bound job (or one that goes into an infinite loop) will not encounter a wait timeout, since it is not waiting. The long diatribe about the need to "keep sending stuff" and problems with long compute-bound jobs is totally off the mark. The data channel may stop due to flow control, and may stay stopped for long periods if the printer is very busy. This is perfectly OK and won't cause a timeout.
Don't disable the wait timeout. The whole point of the wait timeout is to prevent the interpreter from being indefinitely tied up by a host application that has crashed, a communication channel that has been disconnected, or whatever. This is particularly important for networked printers. The only situation in which disabling timeouts is appropriate is when debugging applications or drivers, since you don't want the printer timing out while the host is at a breakpoint or something.