Shopify is a hair more expensive than some competing processors, but when I last dealt with it, they were in league of paypal, stripe, square, etc, so it wasn't a differentiating factor for us, and I suspect that's true for most businesses of our size.
I get that using stripe or paypal it's easier sometimes, but for woocoomerce and alikes you usually have plugins already developed to use other payment platforms.
If Shopify means they hire this guy for a tenth of the time, they save $9000.
They would have to be moving 300k/mo for hiring a full time to even break even.
In any case you can do what everyone else does, bake the fee into your prices and call it a day - it's not like you can compete with Amazon on the low-prices front anyways.