Counterpoint: as someone who's also raced both to a sufficient degree to know (from well before GPL to rFactor and iRacing in terms of simulators, and in KT100, Super Comp and other real-world categories), the skills are far more transferable than you're indicating.

There's still a big difference between the two, but "almost nothing in common" is not an accurate description. And there's a reason the top guys on either discipline can switch over and still be quite competent–if not world-beating–on the other side.

All of the top teams use simulators based on commercially-available simulation engines to develop the car and solicit feedback.

The skills are largely transferable for many drivers. There are a few odd cases–Michael Schumacher famously became too motion sick in the simulator to use it–but those are exceptions. Maybe you're one of them (and if so, you're in very good company!)