I started thinking a number of months ago about why Shopify hadn't yet made subscription processing native to the platform. At the time, I was satisfied with the idea that they were unwilling to store CC information on customers and that was the end of it.
Over time, I began to notice more and more potential features which would be quite simple to introduce natively, yet were still left to app developers. In the previous year, I have only seen one notable instance where Shopify has actually deployed a feature which stole a huge market share away from developers: reviews.
Why leaving minutiae development to independent parties is an intentional and sound tactic
Shopify is leaving plenty of low-hanging fruit on the proverbial tree for tenacious developers. I can't really imagine an argument against that fact. This list attempts to provide tactical reasons for this.
Avoid feature creep while focusing their considerable dev talent on infrastructure improvements.
Radical new features are deployed independently. Shopify's app marketplace allows feature maturation to happen at the risk of someone else's money and reputation.
When an independent developer launches a new service, they have spent their own capitals. They risk their own losses of money and reputation on their investment, with the notable potential upside of mass integration.
Creation of concrete B2B-level "reviews"
This is a big one, and it goes hand-in-hand with the next point. By allowing profits from low-innovation feature shipping to go to independent parties, those independent parties have a nurtured dependence on the platform.
If your revenue is dependent on the success of the Shopify platform overall, are your word-of-mouth reviews going to be all that unbiased?
Diversity over dictatorship
This is all about entropy. Economic entropy, at least. I've said it before: Shopify's long-term success is directly dependent on the ability of merchants' and service providers' continued ability to be successful on that platform. This is so simple, it's nearly tautological, but there are a number of approaches for the achievement of this goal.
Shopify could have easily approached this in a dictatorial fashion, something along the lines of:
we must deploy every feature possible to encourage success! This unwashed mass of developer proletarians cannot be trusted with our precious features!
This, they have not done, and I believe it's example of great foresight. Diversity is crucial. I believe that Shopify is intentionally leaving the platform as roomy as possible for improvement, leaving plenty of seats for "little guys".
I predict that Shopify will continue to leave plenty of room for necessary improvements to its platform. The features created by a huge army of independent developers, regulated by market forces, will lead them to complete dominance in their space of independent merchants.
Once their position is secure, their attacks on the service sector of eCommerce will commence through enabling their ecosystem to do so; larger competitors will not be able to compete with their numbers, infrastructure, or abilities.