The MCU Revealing Thanos" Age Would"ve Sabotaged Infinity War & Endgame

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The Marvel Cinematic Universe revealing how old Thanos is would have sabotaged Avengers: Infinity War and Avengers: Endgame. Thanos was the MCU's first Saga-wide villain, with his defeat being the event that marks the end of the Infinity Saga. Avengers: Endgame's ending featured Thanos from an earlier timeline, as the original was murdered by Thor after snapping half of the universe's population out of existence in the previous film.
Thanos' appearances in Avengers: Infinity War and Avengers: Endgame were impactful. The villain was essentially the main character of the first film, with the movie following the Mad Titan as he traversed the MCU, collecting the Infinity Stones. The second film took a different route with the villain, having an earlier timeline variant of Thanos find his way to the present-day MCU. Both films did a fantastic job of making Thanos a complex and sometimes relatable villain. All that could have been damaged by the reveal of how old Thanos is.
The MCU Thanos Is Younger Than Loki & Thor

Avengers: Infinity War sees Chris Hemsworth's Thor state that he is 1500 years old, and based on a Thor flashback scene, Tom Hiddleston's Loki is most likely 1054 years old when Thanos kills him at the start of the movie. While it is never addressed in-universe, MCU director Joe Russo confirmed Thanos was around 1000 years old in 2012's The Avengers when he first appeared in the MCU. Based on that, Thanos is younger than Thor and Loki, which, if revealed in one of the past two Avengers films, might have proven itself to be distracting.
Revealing Thanos' Age In-Universe Could've Repeated A Villain Cliché

While the reveal that Thanos is younger than Thor and Loki might have proven itself distracting, the villain's age being addressed in one of the past two Avengers films would have been worse for another factor. Thanos being revealed in-universe to be around 1000 years would have repeated a long-running villain cliché idea that is based on villains being described as an ancient evil or timeless threat. Thanos seeming like a more mortal being imbued with great power made him a better and more engaging enemy.
Thanos was the Infinity Saga's main villain, so having him be related to that cliché idea would have been a form of self-sabotage from the Marvel team, which is possibly why his age was only addressed by Russo. Thanos' biggest strength was in how his argument of balancing the universe due to a widespread end of resources thanks to population growth touches on a current topic in real life, so focusing on the character being some sort of centuries-old villain could have taken away from what made him be such a resonating antagonist. Based on that, it is good that Thanos' age was not really focused on in the MCU.
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