Avengers 4: 9 Ways Thanos Could Be Killed

6. He's Trapped In The Quantum Realm Forever

Perhaps there's a reason why Ant-Man And The Wasp establoshed that the Quantum Realm is impervious to the effects of the Infinity Gauntlet? Perhaps the inclusion of tardigrades in there was supposed to show that it can be an eternal prison where time doesn't matter and all outside influence is removed?

Maybe we got to see that to foreshadow the dimension becoming a tomb of sorts for Thanos.

According to one theory, The Avengers will discover that the Quantum Realm could be used that way and will lure Thanos into the it, where a final battle will occur and Thanos will be defeated and stranded. It states that the Gauntlet will be left there with him (after the Avengers use it to escape), since it will be useless within that dimension.

It's a left-field idea, but it could definitely explain why the Quantum Realm is said to be so important to Avengers 4.