OK, my three cents.
1. Not everyone runs 12 tooth pinions at every race. Read my reports and you will see there is a variety based on the tracks. Even on a King Stock Cars are usually geared 10/26, F1s 11/27. Oh and who has tried to tech for a spec pinion with 20-30 or more racers? You cannot count the teeth on most cars unless the rear is taken apart to allow a complete view of the pinion.
2. Having teched thousands of cars over the last 16 years I can tell you that those having problems are usually due to poor set-ups. I try to point them out to the racers but it's up to them to correct it and learn from it. Everything from body mounting, endless amounts of lead wire, guide freeness, frame straightness, bent hubs, etc. How many racers really check their cars after a race to ensure everything is OK?
3. Lots different controllers out there and and the one thing I notice with those saying Retro is too fast is their use of very sensitive chips in their controllers. For example the typical Difalco comes with a 148 but some feel they need to run a 113 of even less when in reality they should try a 180.
4. Over-oiling fronts to the point it causes the rubber to come off the wheel.
5. Our tracks have a typical voltage of 13.6 to 13.8 and thanks to the raceway owners/staff all prepping them the same way it has taken the endless testing of tires out of the preparation. It is typically Wonder rubber run out here. Take your pick on which one you like due to cost, etc.
6. Motors get hot and some really hot on fast Kings and it's not all due to using 12 tooth pinions. Some winds get dark and as noted above the motor still runs fine for many more races.
7. We have lost racers but not due to the speed. Old age, health, death, etc. We have seen an increase in younger racers. They haven't experienced the "fumes" yet (gas and perfume) and maybe with all those electric cars coming out it will just be the perfume.