In the last two seasons under Ancelotti, they have also managed to win the title despite Real Madrid having suffered injuries to several key players, except for the previous season, which was a complete failure. Real Madrid is one of the strongest teams in Europe thanks to their experience and mentality, so whatever the situation, this team will remain a title contender. Xabi Alonso is a bit of a doubt, but if given the trust, I'm confident he can lead Real Madrid to success. Although his first season won't be easy, he needs to adapt to the new system he's building.
That is definitely true, they reacted as if Ancelotti was a terrible manager during his sacking, but the reality is simple, he won 2 UCL and 2 la liga titles while he was there, and I am sure some cups too that I can't really think of. There aren't really anything else that we could see about this situation.
So we can't really see the current situation suddenly better, because while Xabi has proven himself at Leverkusen, Ancelotti also won 50% of the la ligas he managed, 4 years, 2 titles, and same for UCL as well. Without injuries, he would have probably do a lot better next season as well. There aren't that many situations that can get better, Ancelotti could do great this season as well, considering the team, as long as they stay healthy. So, Xabi has a huge chip on his shoulder.