We can see Hazard when he was at Real Madrid, previously he was a great player, he was even the player who was the main choice at his previous club. However, when he couldn't compete with other players in the squad, he became a player who always sat on the bench. This has the potential to happen to all players, including Mbappe. Even though he is a star player, he also has to work hard to always perform well.
True, but I think there's a big difference between Hazard and Mbappe.
Hazard was popular because he joined Chelsea and can play very well for few years.
But, Mbappe was popular even when he was playing for Monaco, after he joined PSG and can show his capability for one season, his popularity keep increasing.
What I want to say is Mbappe can always consistent while Hazard only appeared for few years, just like ordinary great players.