steam is one of the few commonly used 32 bit apps left on linux.
I imagine most of it is bc most other things are oss and have been updated/rebuilt already. having to run a 10 year old binary happens way less on linux than it does windows.
a handful of distros have tried to remove 32 but support they've gotten backlash bc they'd lose steam support. linux the kernel won't drop it any time soon, but there's a good chance that if steam drops 32 bit, so will fedora etc
the trend of serverless means that people are writing a ton more programs that are smallish single endpoint things. not that a ton of people are using java there, but that was a major motivation for c#