I don't disagree with this statement -- It's really hard to gauge the TdF warm up races like Suisse or Dauphine. On paper the fields always look strong but half of the favorites are only there to test their form. The field in the TdS was pretty weak this year, on top of that. The mighty Patrick Konrad was third at more than 3 min behind Bernal, who only took 19 seconds on nutty Rohan Dennis.Maybe worth looking at the opposition before declaring TDS a better win than Tirreno and Romandie.
One thing that seems indisputable is that it's a lot harder to win the TdF than the Vuelta. Parcours aside, every single rider in the TdF is going hard, every stage, because they know it's the biggest cycling platform in the world. And teams only send their best riders to the Tour.