>
most of them wont move "past the out of the box limits of things like WooCommerce and Shopify"Many of those who never move past that phase were likely not candidates for custom development anyway. They'd likely have sold on eBay or Amazon, whereas Shopify offered them the chance to have their own "store".
That is, many who can spend $29/month (or whatever) for a Shopify store wouldn't have been able to spring for $5K or $10K+ to have a custom store built. I would bet that's the overwhelming majority of Shopify customers.
So, arguably, you might even say Shopify helped some companies to get to the place where they can afford custom development.
But, this whole store thing is just a narrow focus anyway WRT the idea of obsoleting devs. There are plenty of more complex/differentiated businesses that have sprung up since e-commerce, and by the time any of those things have been commoditized, there'll be still more to take their place in this ongoing evolution.