Over at The History Of The Web — a site I highly recommend if you're remotely interested in the subject — Jay Hoffman traces the history of offline browsing from the downloader apps of the early 1990s, through the short life of PointCast and on to the Progressive Web Apps (PWAs) of today.
PointCast ended up as a cautionary tale. It’s been cited as an example of dot-com excess and missed opportunity. But it also represents the culmination of a real need, one that was cast aside for almost 20 years before it was rolled into the web platform once again, this time in the form of Service Workers. We can’t reliably be connected to the Internet at all times. And with offline browsing, we don’t have to be.