Fallacies of distributed systems
Network is much much more reliable than it used to be. In a typical large-scale datacenter today, it is becoming common to deploy clos networks with multiple ECMP paths to get from one server to another. Also, cost of network relative to cost of the server is quite low (less than 8-10% of overall cost). Also, fat connectivity between datacenters in a metro area is much much cheaper than ever before (due to huge increases in fibre capacity in the last 10 years). If anything, network has become cheaper faster than compute has in the last 10 years. (And storage has done the same at an even higher rate). So, this affects architectural decisions in very interesting ways. Of course, public cloud make a huge profit on network bandwidths by billing to customers based on old mental models.