They can, and are supposed to, but they have morphed into a box-checking exercise used to keep politicians and professional guilds happy and management asses covered. Hence the reason most of these professionals see the requirement as a burden. I felt the same way back when I was actually working as an electrical engineer.

That said, self-study is a different animal from the side project nonsense that the thread root is referring to. I personally engage in a significant amount of self-study. Some of it a roll back into my day job, some I experiment with in my free time, the rest is purely academic knowledge acquisition. I don't have anything tangible to show off, though, because most everything I have done off hours is the software equivalent of a carver or welder practicing with scraps.

Maybe that isn't the right attitude for a programmer, but in that case a programmer is a different animal than any of the professions listed previously.