Experience helps in a team. Saying experience doesn't matter in a team makes me wonder how well you understand football. I don't mean the team have to be filled with 30+ players, the team just have to find the right balance with the experience and young players. It has to be a mix of both. When a team is too young they lack experience. There are parts of the game that require just experience. We saw how influential Modric was when he came on in the second half of the champions league last season, experience helps you do that.
Ronaldo didn't miss the penalty because he was old, either he was just unlucky or his technique was poor. It could also be that the keeper did a really good job. Ronaldo missed a penalty in his young age at United, at his peak at Real Madrid, so missing a penalty at the twilight of his career isn't a big deal. Even Messi missed a penalty in his prime.
As long as a player is still good and strong enough to play, his experience will mean a lot to them team.
At Madrid, nobody can do what Modric does, despite the fact that he's old. He's the most creative midfielder they have. He understands to the game better than all of the. He may not be strong enough to run all game and win back balls or compete for duels, but when he has the ball, he knows how to make use of it.
Madrid might do fine without him, but I believe their odds of success is better with Madrid around.
Experience definitely matters in sports and football is not an exception. Take a look at the Olympic Games there is a space for older player to be included by each nation just to add experience to younger players. A team filled without experience easily run into crisis. Real Madrid were actually considering allowing Luka Modric to leave this summer but opted against it when there option to stay Toni Kroos choose to retire. Modric was already wanted by some various clubs like inter Milan which shows that the player could still have remained in Europe even if he had to leave Madrid, that’s how important he is still his.
Concerning a team experience matters a lot because during period of downs it is this experience players that the younger players look up to. The issue of Ronaldo mention is a good example, when Ronaldo missed the penalty he became emotional and that was his nature but the ability of him to get back and take the first plenty is what character showcase. In moments like that a younger player will have definitely succumbed to failure and wouldn’t be able to take the next one that will leave other players in fear. We could see when Ronaldo missed the spot kick many of the other players went upto him with talks about the team needing him to stand up to the challenge, that’s what having an experienced player in the squad means, he leads in terms of difficulty