It depends on your timeline used in judging a riders transformation. If a rider comes from nowhere to finish second in La Vuelta in September then goes on to win next years Tour then it’s not suspicious next July? Using your metric the 2013 version of Froome was not suspicious as he had been building form for 2 years.I'm not arguing he's clean, just that this shouldn't surprise anyone, looking at last years results.
Last year was Vingegaards big breakout performance but he’s refined and improved it this year so that the improvement appears more incremental.
We’ve all seen this movie before.