If we lived in a world where people or agents could define those service boundaries up front, correctly, with some reasonable foresight for change on the horizon ...then sure...I'd agree.

However, our world is not that world. Your agents may be happy in their tiny walled kingdom of toil and ineffectiveness, but you and your users will not. Poorly drawn service boundaries will drag you down more than almost any other architectural mistake.

If there is one universal amongst organizations, its that they love walls and silos. Be wary of putting them up ahead of time, cuz tearing them down once established is nearly impossible.