As for his team performance this season they haven't had a thorough run like other previous seasons, you'll agree with me that there has been a fall in their form, therefore you shouldn't be in haste to assume that Real Madrid can defend both the champions league and their domestic league title. In the domestic league Barcelona has an upper hand in their head-to-head this season and despite RM currently standing as league leaders, the gap difference with Barcelona and ATM is nothing significant because with just one or two match lost ATM and FCB will close in on them. So why the much confidence?
The assumption that Real Madrid will be able to defend both the UCL and La Liga is faulty. Yeah, anything is possible in football but they are not as consistent as last season. The club might not get the automatic eight automatic slots for the round of sixteen putting them in a tight corner to struggle for the eight remaining slots in the playoffs. In the La Liga, they are not doing badly. Truth be told, they might be able to win just a trophy this season because of injuries and a drop in the general club performance.
I don't think there's anything wrong, because this is just an assumption or prediction that is made. Maybe I would say it's wrong when someone claims with certainty that Real Madrid will retain the La Liga title and also the Champions League. If it's all just an assumption, then I think it's valid.
You're right that they're not as consistent as last season, but they still have the potential to be more consistent. The opportunity is on them, it's just a matter of how they can be more consistent.
In a prediction, we can't say it's wrong or right, because what is seen is the result of analysis, so it could be that it doesn't happen and it could be that it happens.