I think it would be interesting to be able to hire a merchant NPC to loot for you. You'd lose a bit of the value (say, half), but the merchant would reinvest those profits to carry better items, and they'd give you a discount.

You'd have an incentive to look through the loot to take what you want, as well as an incentive to ignore the stuff you don't. That way you get the immersiveness of an encumbrance system, without most of the tedium.

The downside is with a realistic encumbrance system, you'd either:

A) Not be picking anything up, or:

B) Making so many milk runs your head will spin from the tedium of ferrying useless bullshit back and forth.

Being 70-80 hours into STARFIELD, there's non-cheating ways to avoid the encumbrance penalty, such as the "Powered Assist" backpacks which lowers O2 / stamina consumption by 75% when overencumbered. You can also deposit your loot into your ship's cargo bay and sell directly from it by pressing Q at any vendor.

In ITR/Into The Radius VR, a fully realistic military looter shooter survival horror like STALKER; I picked up and carried EVERYTHING, but through the use of an inane amount of utility items, such as a chest harness, backpack, lower back bags, leg bags, thigh bags, and so on. (My favorite thing to put in my belt bags was cake slices and energy drink cans, made for hilarious streaming content when you take a bite of cake in a dire situation)

I still spent like 20 real-life hours slogging knee deep through swamp to ferry back an entire inventory of artifacts worth 5K/ea.

So my takeaway is, people are gonna loot and hoard; if they do that, encourage it. If not, reward the player with more credits from missions and other things that don't involve scraping and strip-mining every planet for every ounce of metal.

Honestly, realism justifications for encumbrance outside of survival-type games where basic biological needs are the core gameplay loop have always been silly to me.... but the latter one about wheels of cheese rings true.

To me the argument is "what does optimal play look like"? Without encumbrance, there's no reason not to pick up every wheel of cheese, so optimal play is to pick up every wheel of cheese, which is tedious and dumb. But with encumbrance, every wheel of cheese becomes a tedious decision, and completionist-optimal play is to burn endless time ferrying stuff to the shops or storage or whatever. But as you said, making every wheel of cheese not something you can pick up breaks immersion.

So what's the compromise that actually makes sense for the "wheel of cheese" problem? A realistic setting is cluttered with "slightly-useful" items. Don't put so many "slightly-useful" items outside of settings with NPCs that will have realistic reactions to you stealing their stuff? But coding those realistic reactions ("uh, you're The Savior, I guess you can steal all my food... a bit... okay that tears it call the guards!") would be some more dev-work in these already-bloated projects.

But the problem still exists in hostile locales. A lived-in enemy camp is going to have store-rooms of "slightly useful" stuff. If the hero stops to raid the larder while massacring nameless Stormtroopers, is that a problem? I can see the immersion argument that "well, if you can, you probably should since you might need it and that breaks immersion" and therefore that justifies the encumbrance idea, but I also see Steph Sterling's argument "this is just a game and I wanna!" And I have trouble defending realism in these games about butchering your way across the landscape without ever stopping to poop.

It depends on the kind of tabletop rpg. In old school ones you may have a cart and hireling to carry this stuff, so you would definitely take those cheese wheels to sell them or for food to your group that's not so small anymore. Logistic was part of the game. But a part that's easily lost depending on how you play.