system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] Why do the ultra-powerful, cosmic beings allow the infinity stones to be freely available?

We see that the infinity stones have been collected and used by beings like Thanos, who although very powerful, are still just mortals.

Which means, ultra-powerful beings like Galactus or Eternity should have no problem finding and collecting them. So my question is, why do they not do this?

I could understand them not wanting to use the stones, because they wouldn’t want to mess up the natural order of the universe, but why allow mere mortals to have access to them and potentially completely destroy all of reality?

Like, these beings must be aware of the stones and how they could easily be used against them if they fall into the wrong hands. So why not just find them, hide them away, and protect them so that the stones could never be a threat to their own existence and the natural order of things? As it stands, surely someone like Galactus would be paranoid that some dumb mortal could find them and wipe him out with the snap of their fingers, so he should have a vested interest in ensuring that doesn’t happen.
gpt
In the comics, before Thanos, nobody knew what the Infinity Gems could do.  Thanos was dead, and Mistress Death assigned him a task -- kill half the people in the universe.  Thanos told her he needed to do some research on that, and she let him use the Infinity Well (sort of a "magic mirror on the wall" in her realm that can answer any question if you know what to ask and have the patience).  So he basically spent several years down there asking it questions, until he got to the *right* question.  And that's when he learned the true power of the Infinity Gems.

Thanos was the first person to figure it out.  Now arguably, beings like Galactus or Eternity might have known what the gems could do.  But either they didn't know, or they didn't think anybody would ever do it, or they just didn't think about it.  The Infinity Gems are sources of great cosmic power, but individually they don't do much more than bump you up to a high tier superhuman (like Thor class).  And that's if you really know how to use it, which most people don't.  There are lots of cosmic doohickeys out there that are more impressive than a single Infinity Gem.

And as far as hiding them, the Gems *were* hidden.  Not only were they hidden, they were guarded by incredibly powerful defenders.

The Soul Gem was possessed by the In-Betweener, an entity that can sometimes rival Galactus in power, and at the least is a Silver Surfer-level being.  He didn't even know what the Soul Gem did, but he's a petty bastard and he's not going to give it up to anyone voluntarily.

The Champion of the Universe had the Power Gem.  Imagine a cross between Superman and the Hulk, he's immortal, and all he likes to do is fight.  He also doesn't know what the Power Gem does, it's just a good luck charm/trophy to him.  Secretly it augments his strength.  The only person who ever defeated him in direct combat was the Silver Surfer.  So he's pretty tough.

The Gardener had the Time Gem.  He's an Elder of the Universe and has vast cosmic powers.  He has tangled with the Hulk before.  Like the others, he used the Gem subconsciously.

The Runner is Marvel's version of the Flash, except he is immortal and runs in space.  He holds the Space Gem, and is the fastest being in existence.

The Collector had the Reality Gem, and he doesn't part with anything valuable, pretty much ever.  He's also got a bunch of amazing technology that he uses to protect his stuff.

Finally, the Mind Gem was held by the Grandmaster.  He is not quite Galactus level, but he's the ultimate schemer and game-player.

Each of these guys is an Avengers-level threat by themselves, without the Gems.  Normally the Gems would be safe in their hands.  It just so happens that Thanos is actually even more dangerous, and even then it took a very long time for him to become aware of the capabilities of the Gems.