The existence of trained plumbers does not mean no civil engineers are educated, or no environmental scientists exist.
We already have something like union rules so that wouldn't be much of a change. I got yelled at for moving a monitor across a cube without having a A+ cert. I'm like, dude, I have a CCNP, I build my own ham radio gear and microcontroller stuff at home, I've been building computers since that meant hand soldering S100 boards, and I've been doing this stuff since before you were born (literally). Oh OK then I won't write you up ... this time, but don't do it again (WTF?)