If Outer Wilds had collectibles it would have ruined the game. Collectibles have their place but they compete with an authentic sense of adventure.
When you know you've collected 1 / X objects you assume two things: they'll be hidden everywhere, you'll get a cool reward for finding them all.
If you like collecting them, you're not playing the game wrong. You're playing two games in one. One's a game of collecting things the other's the game where the fantasy takes place.
Aside from collectathons, these two games compete. Some players don't mind. For those who do mind, I hope this post can help you articulate why they get exhausting.
Because of collectibles, you move the camera all over the place to find them, not because of a cool sculpture or beautiful mountain in the distance. Your exploration is collectible-mediated and many collectibles just sit somewhere for no coherent reason.
A vault may hint at a treasure. But when collectibles are involved, a weird hole in the ceiling rewrites the scale of importance of props in the level. A vault now is as relevant as the nook between a rock and a wall.
Exploration becomes non-diagetic, you obsessively explore dead ends because you've gone 5 rooms without finding any new collectible so you assume another one is due already.
If the game's all about getting those collectibles and the level is built around finding hidden places, then you get a nice collectathon. Which works best when the level are atomized, you teleport to them, they have boundaries. Collectibles and the world are built for one another.
But when collectibles are thrown in as a side-quest beside the main adventure, now the collectibles start to choke out the real quest.
You're look at strange corners instead of looking at the scenery, you jump to your death down a hole that looked like a secret path, you spot a precocious collectible and spend 10 minutes trying to reach it only to much later the actual path that was much easier.
When you commit to finding them, they'll side track you and break pacing. That's because they could be anywhere.
Even if you choose to ignore them, every now and then they remind you that they exist when you find one by accident and you're reminded that there must be a point to them, something you'll miss out.
If Outer Wilds had them they'd compete with the authentic curiosity of exploring the solar system, they'd make you wonder if a place exists for lore reasons or if there's supposed to be a collectible there you didn't find, they'd lead you down a path that only serves the collectible and not the story.
Maybe you thought Outer Wilds needed collectibles, that it was too basic without them. Maybe you'd have enjoyed finding them all. But I doubt the world would have felt as magical as it did with collectibles.