I'm not sure how much money they'll actually get from this.

The (50,000 employee) company I worked for had very slow IT processes at the time, but when the licensing changed they treated it like a critical security vulnerability because of the amount of money involved: they very quickly migrated their software packages to include non-Oracle OpenJDK builds & rolled out an update to uninstall Oracle java from all PCs. And all server owners were given a deadline to migrate or start paying recovery costs.

I imagined it'd be smaller organisations which would've sat on this issue.

And now it's going to become quite literal debt

It's anything above Oracle Java8u201 more specifically, and some versions like Java 17 are currently free to use commercially.

I was part of the cleanup team where I work (force-uninstall on all machines through MECM, GPOs, and through Intune for macOS systems), good fucking riddance to these legacy apps.

In some cases they think that Oracle Java is somehow better than OpenJDK.

It usually comes down to what's supported by the software vendor. OpenJDK certainly works, but it's a corporate check box.