But again, that's conflating web connected or even web required with mainframe compute and it's just not the same.
PC was never 'no web'. No one actually 'counted every screw in their garage' as the PC killer app. It was always the web.
One of the actual killer apps was gaming. Which still "happens" mostly on the client, today, even for networked games.
In time Mainframes of this age will make a come back.
This whole idea that you can connect lots of cheap low capacity boxes and drive down compute costs is already going away.
In time people will go back to thinking compute as a variable of time taken to finish processing. That's the paradigm in the cloud compute world- you are billed for the TIME you use the box. Eventually people will just want to use something bigger that gets things done faster, hence you don't have to rent them for long.
Umm... I had a PC a decade before the web was invented, and I didn't even use the web for like another 5 years after it went public ("it's an interesting bit of tech but it will obviously never replace gopher...")
The killer apps in the 80s were spreadsheets and desktop publishing.
You know that the personal computer predates the web by quite a few years?