Scenario 1: People are starving. There is not enough food available, at any price, to meet the need, and there is a hard lower bound on how much is needed. We say that there's a shortage of food.
Scenario 2: There is a supply-and-demand situation for some limited good, and some who desire to use that good get priced out. This is the normal functioning of a market. Those who get priced out, though, complain about a "shortage" of that good. What they actually mean, though, is not an absolute shortage, but a shortage at the price they are willing or able to pay.
I think the STEM shortage is the second kind. Sure, your company could do all kinds of nifty things if engineers were abundant and free. That doesn't mean there's a "Scenario 1" shortage, though.
In the meantime, the engineers want jobs that pay twice as much as their current ones. There's a "shortage" of those, too.
It's clearly not a shortage in the economic sense, but it still makes sense to frame it as such, if you're buying labor.
Plenty of jobs.
It's almost as if we want people to train themselves to work doing hard stuff and also don't want to pay them to do it. In other news, water is wet.