How does that scale? It's more than just 'branding' or pretty colours. What about actual featureS? There's the standard say there's the standard 'airline' app,

How does that scale? It's more than just 'branding' or pretty colours. What about actual featureS? There's the standard say there's the standard 'airline' app, that handles booking flights and then the lifetime of managing that booking. Reserving a seat and so on. Airlines build the data and the APIs, OS vendors (?) build the frontends. Then Singapore Air or whoever comes out with a new product/service - you can book time in an onboard shower. The 'standard' doesn't allow for ancillary service bookies, so how does Singapore Air get this to their customers? Go through the 'standards body' and wait for that, rather than just building it into their own app that they control end-to-end. In reality, there are too many variations between different companies offering the same service, that it would be rather infeasible to have a single contract they all follow (without compromise) to develop these provider-agnostic client apps. In a way, browsers and native mobile SDKs is the solution to that problem - browser/OS vendors have created clients for common APIs and widget toolkits to create interfaces. The 'hard work' in delivery an application has already been done (no need for the bank to worry about HTTP, or building widgets like text fields), leaving them to delivery 'just' the layer on top of that.