I'm not writing him off. I see him almost a sure thing for a top5, but in my opinion he lacks that little bit of extra to be a GT winner in this field. He's been very consistent, always as a 4th, 5th, 6th best climber in the race, but I never saw him do a performance that would set him apart from the others, a performance where he could make a difference. His best climbing performance was probably in my opinion from his stage win in Pais Vasco (2018 I think it was), but nothing extraordinary since then.
Lopez on the other hand has a couple of performances every GT (not in this years Tour though) when you go "wow, this guy is the best climber in the race". He is very inconsistent, that's true and I agree. I also agree that they both compliment each other very well. I think in one vs one situation against Roglič, they can't beat him (considering the ITT). If they work together as a duo they have a chance.
Edit:
Or even better as a trio with Valverde.