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.
There are still many matches left for a big change in the points table. It is almost the end of the season, there is no alternative to the consistency of a team at the end. If you cannot be consistent now, then playing well all season will not be of any use. Real Madrid's loss against Real Betis does not make Real Madrid a weak team, maybe they can lose one match. Real Madrid is still a big threat for Barcelona and Atletico Madrid. Because the gap in points is still very small. 1 match will be enough to change the position. So every team now has to focus on consistency. If someone is consistent with negative results, then the great results of the whole season will not be of any use.
Now Barcelona is at the top of the table. Even then, I would say that the chances of winning the league title are still equal to Barcelona, Real Madrid and Atletico Madrid. Barcelona team had occupied the top spot of the table since the beginning of the season. However, due to some consecutive bad performances, the team lost the top spot of the table. However, now Barcelona has been able to regain the top spot of the table.
Each team will play about 12 more matches. It is very difficult to perform well in 12 matches consecutively. Barcelona also has the possibility of losing the top spot of the table again. Atletico Madrid is 1 point behind Barcelona and Real Madrid is 3 points behind. So if Barcelona loses a match, they will lose the top spot of the table.