Agree with the premise. An excellent example premature optimisation or YAGNI. An alternative is to factor your code by business capability / bounded context as

Agree with the premise. An excellent example premature optimisation or YAGNI. An alternative is to factor your code by business capability / bounded context as microservices endorses. Factor the code as such but don't deploy the logical partitions as physical ones. Keep it all in one deployable artefact, in-process for as long as you possibly can. Use an in-proc message bus first, don't dive into Rabbit until you know you need it. As soon as you require that infrastructure cost for http, mq, monitoring a ballooning of boxes / VMs, deployment complications you'll notice the spike in operational expenditure. Grow you architecture organically.