I will reserve judgement on Alberto until after T-A. Let's see what he has then
He may already be on the other side of his best years, but we don't know that yet. But he is 30 now and very rarely do cyclists that excel young get better at 30, they can only hope to regain their best form.
The Vuelta he Won with 6 race days in his legs since the previous July!!! Granted he had a battle on his hands and had to get creative to do it.
IMO Froome will give him just about all he can handle if Froome has the confidence, race savvy, 3 week recovery ability after being pushed at every opportunity and mental toughness. He certainly seems to have the skills and talent.
It is inevitable that there will be a changing of the guard, it Always happens in cycling. Maybe it will happen this year and Froome will be the man; maybe not. But we should enjoy an epic struggle either way