Maybe if Atletico can be consistent until the end of the season, then I fully admit that the main fight for the title could be between Barcelona and Atletico. I don't want to say that Real is out of the game, but they have been losing points too often this season, and considering that Atletico are very good now, they can hold out until the end of the season better than Real. Ancelotti decided not to strengthen the defense in the off-season and this could be his biggest mistake.
Despite the loss to Real Betis, I don't think we can write Real Madrid off that easily because they will continue to be a threat to both Barcelona and Atletico Madrid. The point difference is not wide, just few losses and the it will be closed. Although the league have gone far and every team is trying to consolidate on whatever advantage they enjoy, that does not mean that the storm is over for Barcelona and Atletico because one of the small teams fighting to evade relegation can still pull a huge surprise on them and the rest will be history.
You have spoken well and I really understand you analysis which will be likely come true but remember the League is coming to an end and at this stage all the teams have started knowing their faith on how the season will end. On this stage of the season even the weak teams get stronger especially the ones in relegation zone because when they realize they have nothing to gain again then their aim is to stop the ones that are struggling for points to make it to the next level. I equally agree with you that despite Real Madrid defeat both Barcelona and Atletico Madrid are not comfortable because they see real madrid as a big threat to them especially when the points is not big margin and with a slice mistake from them Real Madrid can get a slot.