I wonder how many of those are actually still out there. According to Wikipedia, Intel kept making replacement parts (386 and 486) until September 2007, but personally, I have never come across one in actual use. My own career in this field began with an internship in 2008. Since 2016, my day job includes working on a PLC runtime with a code base older than myself, originally written for DOS, but every industrial PC (or other x86 based embedded device) I have ever got to play around with had at the very least a Pentium class CPU in it.

As for the Windows 3.x based industrial equipment: Some industrial devices I have worked on in the past turned out to actually be ARM based, running Linux, but the software went a long way to convincingly fake old Windows style UI or even a DOS prompt. I was once tasked to extend a UI library to reproduce Windows 98 style color gradient borders faithfully.

Only once have I seen an actual embedded 486SX with my own eyes. Last year, someone dragged a weirdo Siemens telephony box to the the local Hackerspace. But obviously not in active use anymore. The box itself had a design language that screamed "Star Trek: Voyager". I found a UART, it was running "On Time RTOS-32" which, according to the German Wikipedia, was developed by a German company and discontinued in 2023. It supposedly has a Windows API compatible userspace.