I'm trying not to pick sides but here are a few arguments they oppose to these key points :
- Technological advancement : Although it does play a role, they measure power in long climbs to limit that bias. Speeds are lower so aero plays less of a role. Bikes were already as light or even lighter in the 2000s. They also calibrate their power predictions against riders of the peloton who publish their power on strava.
- Nutrition has indeed changed, it helps producing near max power efforts at the end of long stages (aka durability) but doesn't play a direct role on pure max power (VO2 max related) which is what they are worried about.
- Regarding training, I'm not really sure, I think the pro peloton already had access to power meters in the 2000s.
- Regarding testing, it's indeed quite frequent but it's not bullet proof.
- I think the history of the sport is so bad it's hard to see the half full glass.