To second this theory with some real-world data. A few startups I worked at a NY scala shop that used tons of Akka (event-driven queuing scala thing). Why? Because a manager at his prior job "saved the company" when "everything was slow" by doing this, so mandated it at the new job?

What were doing that required queueing? Not much, we showed people's 401ks on a website, let them adjust their asset mix, and sent out hundreds of emails per day. As you would expect, people almost never log into their 401k website.

A year or so after working there I realized our servers had been misconfigured all along and basically had 0 concurrency for web-requests (and we hadn't noticed because 2 production servers had always served all the traffic we needed). Eventually we just ripped out the Akka because it was unnecessary and added unnecessary complexity.

In the last month this company raised another funding round with a cash-out option, apparently their value has gone up and they are still doing well!