The rate of change can also be explained by age. To be clear, I know he is doping to the limits but I also think he is the most talented rider in a generation.
I own a number of books on bike racing, bike racers and cycling specific training. I watch,listen and read about bike racing from a variety of perspectives, including current riders, coaches, nutritional experts.
It would be great to see a real age to age comparison between Eddy Merckx and Pogocar.
Clothing, bike weight, gear ratios, race days, distances, nutrition, including hydration. Pro like Geraint Thomas has said that the way he trains, eats and hydration and nutrition are completely, almost 100% different than when he started. Many racers in Meckx era had issues related to saddle sores, hypothermia was a significant issue, dehydration. Another easy difference is body weight and philosophy, Old school riders were carrying extra weight intentionally, it was thought to be a health benefit. Riders like Jan Ulrich talking about calculations for extra baby weight as he started the season, all part of a formula to race and train off the extra and not have adverse health effects.
Many team tables had stacked plates of meat and Eddy era, meat was thought to be the major source for proteins and protective nutrients.. Thinking of Merckx wearing wool shorts and jerseys and the chamoiux ..yikes!!! Pogocar big issues are if he gets a cold sore or hair is sticking out of his helmet correctly..
You could be right and he is fully pharma-d' but I think it's lots of things