If supply for labor goes a bit down, wages will increase a bit, and then companies will be incentivized to replace these bad jobs with automation.
Those jobs going away, and wages going up, is a good thing not a bad thing.
As few people should be doing those bad jobs as possible, and for the ones that do them, they should be paid more.
And does "broadly unproductive" have a specific meaning, too?
This elitist attitude that low-paid workers are "unskilled" workers is bullshit and needs to go.
Now, let's take the average farmer, orchard worker, construction worker, and then chuck them into a software job. They wouldn't know where to start and wouldn't get anywhere without the same educational basics that 99% of developers have gone through. That's not elitist, it's just reality.
So, there's a clear distinction to be made and it's not necessary to water down every word in the English language because we're afraid of hurting someone's feelings.
I wouldn't call "low-skilled" workers _unproductive_ per se, and personally think they're incredibly valuable, but economically, the cost/difficulty of replacing a "low-skilled" worker is relatively low: it's a lot easier to find a replacement farmhand than it is a replacement farmer that manages the farm itself.