Spammers aren't that smart, they will absolutely go where the bar is at its absolutely lowest, if not missing entirely. Just changing your SSH server to operate a port that is not 22 is going to stop most if not all random login attempts.
I wouldn’t characterize that example as “not smart” to be honest. I’m not particularly smart, but if someone has gone through the trouble of changing their secure socket port from 22, I would realize there would be more work and time involved in finding the actual port, and then it would be a safe assumption that, if found, it would have significantly more security hardening than the average port 22 because clearly the admin knows enough to change ports. So I might even characterize it as smart to not go after ssh ports that are not 22.
The reason is different. When you need to scan 5 million IPs on 22 port is one thing, but 5 million IPs times 100 or 1000, then you simply run out of resources and since 99% of people use 22, why bother?