'they' didn't eat the cost of anything, 'we' are paying the cost thru higher prices on everything we buy.
Or you know, California could just enforce the law. But the people have voted and spoken.
I think people would be OK with a fee for returns, if it wasn't high. But asking people to pay retail for returns is not realistic, and I personally won't shop from stores that make me do that.
Free returns aligns incentive structures to where the vendor loses money if they sell me junk I want to return.
I don't do returns hardly ever, because of the hassle factor. I don't buy from vendors who don't support them, because the amount of scammy behavior goes way up.
Also what you say works more for unique direct-from-manufacturer sales and applies less to commodity products sold by Amazon.
There's no need for "free" returns on the PS5 you just bought because that product's reputation is well-known. You're just paying for the retailer's costs to reduce all friction from sales while they get all the benefits.