I don’t think there’s any hurry to do this, just opening an issue as #17503 made me wonder.
In general, running bitcoind in 64 bit is unarguably better. 64-bit registers result in better validation performance and it allows leveldb to use mmap without worrying about virtual memory usage.
Back in the day, the rationale for removing 32-bit x86 builds for Windows but not Linux was that some cheapo VPS still used x86-32 bit.
Is this still the case in the year of (almost) 2020? Is anyone running x86-32 VMs for other purposes than testing software on that architecture? Even with that, how much testing are these binaries getting?
(to be clear, I’m not arguing to remove support for 32-bit, just to stop building and providing binaries for it. I also think ARM is a different matter.)