I'm pretty sure the gold issue is something folks have complained about for quite a while. One of the very, very few criticisms that were acceptable back in the early days of 5e--mostly because it's kind of a humblebrag, if we're being honest. "Look at all this money that I have nothing I can do with..."
But at latest with Xanathar that problem is solved. It offers more options on how to buy magic items and offers more downtime activities between adventures.
Up till Level 6 Gold Player Characters have actually not a lot of Golf RAW.
If you follow the rules of the DMG, a 5th Level Character, at the end of the level, has accumulated overall 658 Gold on average. That is not enough for a fighter to max out his gear, because a plate Mail costs 1500 gold.
A level 10 character, if he doesn’t spend anything, has 16 000 Gold on average.
But only if he doesn’t spend anything.
He could spend it on a ship (5000 to 30000 Gold). Or a castle. Or another homebase.
Or he actually had to spend it on healing potions, living expenses, researching, magic items (he could by up to 3 rare items or one very rare item, if he is lucky).
Of course the DM has to out all that options into the game. But a DM also has to put in monsters, dungeons, NPCs and adventure hooks, so I don't see that as a problem. It is one of the jobs of a DM (in homebrew campaigns).
Like for a wizard buying and transcribing spell scrolls, that is utterly expensive.
My Wizard Character in my current campaign doesn't have enough money to even buy all the spells she wants and doesn't have yet, she doesn't even has the money for the transcription costs.
What I agree is, it could be made easier for DMs to have all that stuff in one place. A real economics section where they explain it more. But the stuff is actually there.
Is that really a thing people are even asking for? But overall yes, if you can only hold (say) your Strength score in total items, and some items are extra heavy and "cost" two(/three/etc.) "slots," then yes, that would be a simpler, faster system, and thus "easier" by some definitions.
Would it lead to better, more interesting gameplay? That's by far the more important question--and extremely difficult to answer without serious testing. Like most non-obvious questions regarding game design and balance.
I'm really not that sure that it does. What is the key benefit that it provides? Because I find that most inventory management systems work, at a very high level, in the same way: avoid letting the bad thing happen. That tends to result in uninteresting, even frustrating gameplay.
It is, in general, better to have a system which rewards good play, rather than one which exclusively punishes bad play, no rewards for playing well. I have yet to see an "encumbrance" or other inventory-management system which rewards effective play in any way. That's a pretty serious drag on it as an interesting and useful component of a game's design.
But you need to "punish" bad play. Running out of food during an exploration quest and having to return home can be seen as punishing, but it is need in order to feel rewarded when you plan your quest well and stock up on provisions and transport capacities like a donkey and a cart or something.
If forces decisions. If forces compromises. Do we leave the donkey behind on order to go up the mountain or are we looking for another way? Do we press on when food is low and hope to find scavenge another food and water or do we turn back?
Like of you play and exploration game and don't use (any) encumbrance system and don't track resources, it just gets boring "we continue searching until we find it". Than the only obstacles are gmtraps, Hazards and monsters.
I really love it, that in Baldurs Gate 3 you need to have food in order to benefit from a long rest. I like it that the make my character slow down when she is carrying 20 swords of slayn goblins.
It also goes into the gold issue. Especially at low levels living Expanse take up a lot of the Gold costs. But if the characters don't need to eat, then of course they have more gold. If I wouldn't need to eat in real life, I would have way more money for D&D

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