La Liga teams comes for the UEFA Champions League title but they're not getting it because the promising clubs are yet to be decided. Don't ever place your trust on these elite teams because the results they eventually generate appears to be inconsistent and confusing most times. For illustration, the exact scenario of Atletico Madrid, they won Real Betis 2-1 and lost to Cadiz 2-0 which is very confusing result. An elite team will not always be in good form this season, rather there are many more actions to be triggered with these teams.
Well I don't think we should just rule out la Liga teams just like that in the champions league because if you could check the records very well, you will actually find out that the top teams who has won the champions league the most has got a la Liga team there so it just that this has revolved around a particular team in the la Liga but then other la Liga team too are aswell trying their best and are very hopeful to do same.
Atletico Madrid has show any form of weakness in thea La Liga and aswell the champions league, they have have a considerable average fair performance so far and should be considered one thats not a weak team or having a performance that will be seen otherwise, the only problem which you rightly stated which I agree that they have got is that which is with consistency, they often some times don't really appear really consistent but the. They do try their best not to easily crash out of the champions league and at least they got passed group stage.
Real Madrid is a la.liga team who has always tried to keep the name of la Liga always well represented in the champions league and has even don much more than some of the English teams who are found in the champions league aswell so la Liga teams hasn't been doing really bad in the champions league and even this season one of the la Liga team is a favourite for the champions league trophy this season.