As all the favorites came together to the last 10 kilometers. If they would be after the overall win, they should contribute more, trying to catch Mollema. Doing that, they would likely have substantially increase the chance of Roglič winning. By not doing that, for sure Roglič won't win, but nor will any other favorite. Now there is a chance Mollema was just too strong today. But i got the impression, other favorites just wanted to finish ahead of Roglič, not caring all that much, if that comes down to being second or first overall.
That likely comes down to a lack of respect, something similar happened on Giro 2019. This will in my opinion change in the future. As Roglič has proven his qualities this season and therefore other favorites, whenever finishing second, will prefer to admit defeat to Roglič, compared to someone else, not even being considered a favorite, before the race started.