I think your theory is fair, but also very few people are actually buying cars.
Hyundai are overwhelmed with the ioniq 5 and 6. The 6 has already broken records for pre sales.
Most hyundai orders are leases, fleet cars etc. If you look on forums most seem to be motability or work cars, so our orders going to someone who wants to outright buy is unlikely.
But its annoying still, my delivery date when from July to march 23. Upsetting but ultimately it is what it is. What else is there? The scheme is being killed off and the cars are getting worse and worse, with over priced APs for very little car.