I'm not a Walmart hater, but as I understand, the company requires their suppliers to open their books for the inventory they sell to Walmart. If the company "makes more money", Walmart will squeeze them to lower their wholesale cost, but that won't necessarily be passed to the consumer.

Essentially, if you get in bed with Walmart, you will make the money you want in the short term, but eventually, if you want to keep that money coming in, you will lose control of your pricing.

This doesn't even get into exclusivity requirements for products, etc.

See Snapper lawn mowers, for some insight to this process.

Make a deal with the devil... and you'll end up at the behest of the devil.