The reason for stealing isn't because it is easy. You don't find enough gold on enemies in EA to buy a +1 warpick and +1 chainmail. You sell gear at 1/3rd and buy it at 8/3rds base price (soemthing like that). The reason you NEED to steal is because you cannot afford it with the ridiculous markup/down. You can steal anything you want in D&D, if you can see it in the shop you can lift it. Why would anyone buy something worth base 100gp for 250gp and sell them it for 28gp? No wonder the trader has a endless pot of gold.
How to solve this? Trader buys at 80% sells 120% of base. Therefore you can get what you need and the trader makes a tidy profit. I am not trading a cow for magic beans, ill just steal it. Yeah and specialist traders makes sense.
I am all for ALT highlight ALL non-hidden containers and interactions. If there is a cosmetic box, you should be able to open it. Would there be 4.45x10^15 empty boxes all over the joint? No and bookshelves hold books fgs. Not bothered about "loads of stuff" as long as there is a use for it. If you look in a box and there is a woooly jumper and some crocks, don't care, don't show them if they are useless in game. In a house you will find stuff that is worth $$$, have a loot filter for wares worth money and crafting stuff. magic weapons, items, jewelry. I actually like the idea of random useless crap all over for the appearance of a lived in world I just wouldn't pick it up.
Loot filter would solve all of this.