I don't know the exact precise reason , but I've been told they have to destroy the dead plants ( pitch em ) in order to get credit for them or not have to pay for them .
Lowes is happy to discount plants however. They take what they can get to recover their loss .
I'm not sure talking with a manager will change their store policy ., but good luck !

The plants at Lowes and Home Depot are a separate entity, I believe. The people that work directly with the plants aren't their employees; they work for a separate company or vendor. You probably could talk to one of the vendor's managers, but each manager usually covers many stores and might be hard to find.

Just last week I was at Home Depot and they had a croton that I wanted but had a lot of dried leaves and asked if they could do a discount and they said they can't cause they don't own the plants, which is so stupid to me. I've seen rotten succulents and flowerless phals still at whole price....why in the heck would anyone want those when for the same price they could get a much better and alive plant. ..where as people like us could try and save some of some of those plants but not at full price....

And the plant I wanted was an exotic angel plant, I've bought those at discounts at other stores, so it makes absolutely no sense to me...EA told Home Depot , just them, that they couldn't discount their plants but told other stores it was okay...?? I just don't believe that....

Go to Lowes for sure! I have had great success in finding some beautiful plants at crazy discounts! Like 75% off! I just picked up this Siam Aglaonema just because it was a little droopy!

Though it might be an exercise in futility, you might try talking to their garden center manager and ask if they would dump out the dirt & dead plant and sell you just the container at a discount. As has been noted, some BBSs are much more flexible with regard to discounting such things than others. IME, Lowes tends to be one of the better ones.

I wonder if it could have to do with their return policy? HD lets you return plants that died after purchase. Don't know if they give credits or cash refunds, just an idea.

As it was explained to me:

Home Depot only pays for what it sells. If they mark something down in the plant dept to sell it to you, they still pay full price to their vendor for the plant.

Your better bet would be to ask the outside vendors stocking the shelves if they sell the pots you wanted.

The dead plants are returned to the vendor. Most often, it is a better deal for the store to return the dead plants and containers back to the vendor and get more living plants than it is to give you the discount.