The average day-to-day work is menial, for example investigating a production issue. That isn't something that people get into as a hobby, that's work in a very unromantic sense. Maybe having good systems background can help in those situations, but it's a little more subtle
I do think though that it works the other way: people who actually care about computers don't care if tech is no longer a money field, they just want to work on computer stuff. And maybe earlier it wasn't as much of a money field. But that doesn't imply that the enthusiasts are better at fulfilling work responsibilities. A lot of work stuff is business specific and not very dependent on systems background
So yeah, I don't think the part about over-hiring is necessarily wrong, but this sort of "I'm better than you" attitude isn't very becoming. Maybe you should give this [0] a read, just to see a different perspective