There are also some users on 10+ year old 32-bit netbooks or
business laptops, both x86 and Apple G4.
The longest-lived 32-bit embedded systems with large memory
(other than Arm) are probably NXP QorIQ P20xx/P40xx used in
military VME bus systems, and low-end embedded systems based
on Vortex86.
I'm less worried about all of these because upstream kernel
support for ppc32 and x86-32 is already bitrotting and they will
likely get stuck on the last working kernel before the
TI/Renesas/NXP Arm systems do.