Do they really though?
The company I work for has 150 employees. Granted, most of those are across various departments in the worlshop, so don't use computers as part of their core work, but we have around 50 PCs around the site.
We don't have a dedicated IT person. We should, but we don't (currently), because our boss is the kind of old skool employer who doesn't really understand why we need that many computers when they didn't have them back in the '70S. I would suggest that there are far more mid sized businesses like that where the boomer owner holds a similar view than you might think. Or I'm wrong and just looking at it through my particular lens. But having worked for a bunch of mid sized engineering firms over the years, little about my current employer strikes me as particularly different from the others.