I don't agree that stars in the Belgium team are too old. De Bruyne is 31, Curtois is 30, Lukaku 29... All of them are around 30 years of age and that is the time when a football player should still play at their best. Especially for the star players like the ones I mentioned. OK, Mertens is a bit old with 35 but he is one of rare players that old in the team.
It is not only about their age, i agree that they are not too old, but their form as a team is not as good as it was, in my humble opinion many of Belgium's players were better around 8 years ago, and if they should have won a world cup, it may have been the ones held in 2014 and 2018, some of their players are not in form now, like Hazard and even Lukaku, de bruyne and courtois are still very good, but the general team are not as good as they were, that is why many people are not giving them a chance in this 2022 world cup.
It just confirms claims that no team in the World Cup can be considered as a certain champion. In 2018 Belgium lost 1-0 against France who later became a champion. Fortunately for them, later they won against England in the match for the third spot and at least they got a medal. England on the other hand was not that lucky and you can't say that they were bad in Russia.