A "Stable, Consistent Architecture" is a myth. It can never be achieved. Over the years, each of us has come to accept this fact, and with a microservices architecture, it is a lot easier to live with this fact. But, that does pose a lot of other issues that we need to look at.
An important hurdle in this journey is that of application integration. A core tenet of the microservice architecture is that any interaction or integration between systems should be based on globally accepted standards rather than a mutually accepted protocol. If we build a system based on a protocol that is based on a simple mutual agreement between two developers, it can never work beyond those two developers. To enable a generic plug and play interface, the communication has to be based on globally accepted standards.