I don't know many businesses that would perform processes that don't make them money. Even if we use your example of next business day what happens on a Friday where the refund isn't processed until Monday or Tuesday? Is customer satisfaction really increased if you get their refund back to them in 3, 7 or 10 days?

In instances where you have to ship the defective product back. They don't send you an over-night, next day label to get the product back to them as soon as possible. They send it ground. So you paid for a product, you then wait for the product, you then call to get a refund, you ship it back, they receive and process and then you get refunded your original amount. That could be two weeks, even though your refund was settled next business day.

I'd be surprised if any retailer takes a loss with a refund that they can't send back to the manufacturer or write off.

It also seems that there isn't any set refund time limit and varies per state in the US.[1]

[1] https://www.freeprivacypolicy.com/blog/return-refund-us-laws...