What's the difference between 1990 and today? AT&T in 1990 was no longer a monopoly; there was competition in long distance, so some calls got through, just as calls went through today on T-Mobile's competetors.
The main difference was expectation. 1990 was still the era of "5 9's" of reliability (99.999% uptime). Telephone services were simply not expected to fail.
We expect phone (and Internet) service today to be MOSTLY reliable, but we're now conditioned not to expect it all the time.