There was a movement to make /bin /sbin etc symlinks to /usr a few back. I honestly don’t remember the rationale, but here’s Debian’s page about the change: wiki.debian.org/UsrMerge. If I hadn’t been following the distros at the exact moment they did the changeover it probably would have thrown me for a loop too.
I think it had to do with the fact that these days relatively few people need /usr on a separate partiton and so it very rarely happens and something about system binaries being easier to manage if they’re actually all in one place. People are ready for some tweaks to the FHS, I guess.