Have we seen any blue collar jobs performed by wizards? I feel like most of what we've seen in the books have been government workers, reporters, shopowners, and teachers. Does the wizarding world have some sort of plumber/construction worker/etc. equivalent jobs? Or does everything just get done by magic?

 

Of course they do. Someone has to make the magical items in the magical shops. They're not all created by the shopowners. The brooms have brand names and companies like Nimbus, etc...

Filch is practically a janitor.

The Quidditch World Cup had thousands and thousands of people. They don't all work for the Ministry or Daily Prophet. Crews were hired to make the stands, I'm sure, and it's not like the Minister of Magic is going to be cleaning up the site the day after.

Just very few of them are going to matter much to the story.

 

I was grabbed by a "We Can Memory Charm it for You Wholesale" (total recall) type plot bunny, but I'm having a hard time coming up with a plausible dead end job for him to be stuck in.

 

A plausible dead end job? Well, remember that not all jobs in the wizarding world are focused around magical ability. A distributor of magical items isn't going to worry if their communications clerk is good at curse breaking. Make him do some job filing requests at a potions ingredient supplier or something. Just because the job doesn't require magic, doesn't mean that a wizard isn't going to do it. Muggles don't seem to find their way in to the wizarding world very often, and I doubt that many of them take wizarding jobs if they do.

 

Speaking of which, what is the point of having Filch there. I mean, Hogwarts employees over a hundred house elves, who can clean better and faster then Filch, who is also a squib, so all the cleaning he does is done muggle style.

 

Filch was introduced before House Elves, and exists as a foil for midnight wanderers. Likely, JKR had not yet thought of House Elves when she created the character Argus Filch.

 

But why would some of those jobs even exist in the first place?

They seem to do everything with a flick of their wands, including stuff they have no reason to do (like stairs moving randomly); this was brought up in a fic I've read; they seem more concerned with "Can I do it?" than with "Why should I do it?"

So, I don't think many jobs like those exist.

Unless, of course, if they were created to employ squibs, like Filch, who'd surely feel unconfortable in the muggle world; yet another reason for them to be bitter, they have to take pity jobs.