> but it just wasn't IBM's software that people ended up buying.

Well, I mean, WebSphere was pretty big at the time; and IBM VisualAge became Eclipse.

And I know there were a bunch of LoB applications built on AS/400 (now called "System i") that had "real" web-frontends (though in practice, they were only suitable for LAN and VPN access, not public web; and were absolutely horrible on the inside, e.g. Progress OpenEdge).

...had IBM kept up the pretense of investment, and offered a real migration path to Java instead of a rewrite, then perhaps today might be slightly different?

Oh wow I didn’t know Eclipse was an IBM product originally. IDEs have come so far since Eclipse 15 years ago.

And while I’m writing this I just finished up today’s advent of code using vim instead of a “real IDE” haha

Websphere is still big at loads of banks and government agencies, just like Z. They make loads on both!