Because the majority of people didn't have net even then, let alone let their kids online. My first experience with the net was in 96 but I didn't have actual access myself on my own computer until 2002.Why is this surprising? I've had internet in one form or another since 1986 when I was a Beta tester for the Prodigy online service with my trusty 1200bps modem!
Prodigy was the first online service to offer a graphical user interface, other online services were strictly text based. This all pre-dated the WWW.