I don’t think Movistar are tactically inept, much as I dislike Valverde he did just about all he could do once they got to Ventoux. Someone had to attack to try and disrupt Sky from their usual high tempo until 2-5km to go, then wind it up then Froome attacks routine. Valverde attacked to try and cause Sky’s domestiques to be dropped but they were just too strong.
When Quintana went I think he just realised he didn’t have the legs that day and if he carried on pushing into the red he could end up in serious trouble so he eased off but Froome obviously saw the weakness and attacked, at that point Quintana just had to ride at threshold and limit his losses.
It’s far from over though, unless Quintana has an illness he’ll still be a big threat in the long Alpine climbs. Will be interesting to see how he fairs in the TT today, I think if he loses a lot more time he must be hiding an illness.