Why should an IT job pay more just because something is deemed "less" of an intellectual job. Hard graft has just as much right to pay too.
In this generation, you're more likely to find someone who's good at IT than someone who doesn't mind working with dead animals and has built up the fine motor skills to fillet them efficiently.
In most of these types of jobs, you're not just being paid for your skills, you're being paid to do something that the average person couldn't stomach. In the same way, medium to long haul truck driving now pays very well, but a lot of people can't stand being away from home for one night, let alone 4-5. If you don’t mind travelling for work there are far more cushy jobs as well where you get to sleep in a decent bed and aren’t showering in some ******** at a service station.
Supply and demand at the end of the day.