I think this raises really great points - but I think there is one additional major question too which is "what scale are you dealing at?". If you are handling

I think this raises really great points - but I think there is one additional major question too which is "what scale are you dealing at?". If you are handling billions of dollars in sales, then yes, rolling your own payment infrastructure will probably be worthwhile, but at that scale you will also be getting a very different commercial offer from the payment gateways anyway. If you 'only' have a million dollars in sales, then there isn't going to be a payback here (but there may be a cheaper payment gateway than Stripe). The fees to Visa and MasterCard can't be avoided - even Amazon is having a public commercial spat Visa over fees.