The problem I have with the "just a bad day" explination is that, first off, that's one hell of a bad day but also that he just phoned it in at some point. Almeida dropped earlier but kept fighting to retain a chance at top 10, and he managed.
This phoning it in could potentially mean he can go in breaks, but that's not what this vuelta was about. You should've gone to the Tour if you wanted to do that and it would have been fine. If he had a bad day, I'd expect a GC rider to do what almeida did and keep going and hopefully have a better time next day. Yes you lost your chance on winning but you get to keep racing for a gc, the kind of rider he wants to become. A collapse like this is more psychological than physical.
I've been going on all year about weight, tactics in racing and it's all wrong. They've turned him more and more into a one day rider rather than a gc one, it's all they know at sqs perhaps?