Message Bus != SOA. What the prior poster is alluding too is the Actor pattern and/or Message passing pattern.
My problem with microservices is that your often picking subpar solutions/technologies particularly if low latency is a priority. For example HTTP is not always the best protocol and Request/Reply is not always the best messaging pattern but this is what most people equate to microservice (ie HTTP 1.1 REST a lightweight list of servers (etcd, zookeeper, consuler) or a load balancer).
My problem with microservices is that your often picking subpar solutions/technologies particularly if low latency is a priority. For example HTTP is not always the best protocol and Request/Reply is not always the best messaging pattern but this is what most people equate to microservice (ie HTTP 1.1 REST a lightweight list of servers (etcd, zookeeper, consuler) or a load balancer).