Comment by DowagerDave

I worked in Ecommerce with a company that built sophisticated subscription solutions well before Shopify had a real offering. We took significant VC money, then watched Shopify build out their own solution to service the now proven market. I'd expect them or Stripe to do the same thing here; it's way more common than buying the first mover or hiring them to build it, plus YC has no interest in this sort of business model.