Abandon is too strong a word. I imagine most people who are still using 32 bit operating systems aren't too concerned about getting the very latest version of firefox either.
These things that look like institutions, that look like bricks carved from granite, are just spinning plates that have been spinning for a few years.
When I fight glibc dependency hell across Ubuntu 22 and Ubuntu 24, I sympathize with Firefox choosing to spin the 64-bit plates and not the 32-bit plates.
Employees: “We want to use new feature X.”
Boss: “Sorry, but that isn’t available for our wealthy customers who are stuck on Eee PCs.”
Nah.