Real Madrid is playing very well this season and they were also able to bring in new players when they out of a sudden had to deal with injuries. Both Courtois and Vinicius Junior are key players ad while they found a great solution for Courtois, which was hard enough, it was difficult to do the same for Vinicius Junior when he was injured. But he is back and living up to his full potential. Barcelona won't get close to them, but to put it in a nutshell whether there is still a chance for the title race to become close, it will all be about matchday 32. The clasico will decide whether there is going to be some fighting until the end.
Form always determines the success of any squad. Real Madrid is in good condition this season, and there is not much doubt that they will win the La Liga, since I do not believe Barcelona will be able to compete with them. Real Madrid is already eight points ahead of Barcelona, and they defeated Barcelona in the first leg. With Real Madrid's current form and the points gap they already have, I don't think the El Clasico will determine whether Barcelona can succeed or not, but they should be able to close the gap on Madrid due to their inconsistent play.
Obviously you are wrong about this one. There are plenty of examples when teams that are in top shape and play very well still can get eliminated from any competition. It is highly unlikely in the domestic league though as the team with the best form has the highest probability of averaging more wins than any other team over a large number of games. But in the Champions League or national cups like the Copa del Rey, it is not only about form and it doesn't always determine success. A far weaker team can land a lucky punch any time and eliminate a huge favorite from a tournament. Atletico Madrid would not beat Inter Milan very often in two games, but this time they did. However, their form was certainly no good indicator of their advancement to the next round.
it is not that easy and I think most people familiar with football know that. The leagues have so many games that the best team usually wins. But the other competitions are kind of driven by their own set of rules.