In general markets are pretty good at arbitrage. If you can get a $50 discount for a product by doing X, someone is going to set up a service whereby they do X

In general markets are pretty good at arbitrage. If you can get a $50 discount for a product by doing X, someone is going to set up a service whereby they do X for you, resell the product for a $45 discount and put $5 in their own pocket. At which point nobody would pay full price to the original seller and the convenience fee for not doing it yourself is $5 instead of $50. The problem comes when the original seller doesn't want their price discrimination scheme to be thwarted by efficiency-improving arbitrageurs and takes measures to prevent that, because that's rent-seeking behavior and shouldn't be tolerated.