I keep a 32-bit x86 Mac alive as a hobby project, and I've noticed the same thing. Debian seems to be the only Linux distribution with a maintained and up-to-date x86 port.

edit: I don't want to take up more space in this thread, but would like to thank Vogtinator and saagarjha for pointing out other options for 32-bit Linux distributions.

openSUSE Tumbleweed supports i586 and up.

Tumbleweed is just great!!! That comes from a Arch and FreeBSD veteran.

Alpine Linux supports it.

Well, even many mid-tier phones already have 4 GB RAM now.

The demise of 32-bit was/is inevitable for personal computing.