Some developer user stories may remain simple (e.g. making a charge, sending an SMS) but a lot of the value will be created by systems integrators / service partners who understand the platform's products deeply.
Having good self-service products and documentation for the impatient developer is a necessary (but not sufficient) step to create this integrator ecosystem. Much of the work is on the business side to convince integrator managers that there is a viable market opportunity on your platform. This comes with all sorts of other considerations, like certification, co-selling agreements, reseller pricing, etc.
For all of their faults in product, Salesforce, Microsoft, and AWS have achieved their dominance through successfully building the integrator ecosystem. Hoping Stripe's service partner program takes off in the same way as the platform grows.
I do think that software complexity lifecycle management (and how that pertains to organizational considerations) is one of the tough problems in our industry. AWS has done an amazing job in terms of their pace of development and innovation, but, yes, it's also become a pretty complicated suite. I think we all currently face some kind of "fast development", "cohesive integration", "broad functionality" trilemma and how best to surmount it seems a big open question to me.