32-bit x86 processors are exceedingly rare these days. But we still currently support them in our Windows client. Maintaining that support is not really worth the effort any more. I tried to find some numbers, and the closest thing I found was this: https://www.pcbenchmarks.net/os-marketshare.html That's a performance benchmark tool, so it will likely represent enthusiasts. But even if you increase their numbers a few magnitudes, it's still very few users. Steam also shows less than a fraction of a percent on 32-bit. For reference, we dropped 32-bit servers in bug 5308, and 32-bit Linux clients in bug 7962.
The blocker for this is that our current version of NSIS requires 32-bit. See bug 5422.
