Basically, if you model senior eng time as $5k/week -- not even counting the opportunity cost -- you'll understand why AWS.
While I definitely think AWS is very expensive for the servers, they are not overall expensive. Again, setting up CloudWatch in an afternoon or dumping tons of heterogenous logs into S3 and querying them with Athena or spinning up full environment stacks (front end pool, back end pool, load balancers, databases, vpcs, vpns, etc) is an enormous cost savings vs finding, installing, configuring, and maintaining batches of software to do the same.
edit: pay an eng $180k. Fully loaded, you're looking at $220k plus. Add in either recruiting time or a recruiting fee that probably runs us $2k/mo amortized over the first year on the low end. Add in the fact that the first 6 weeks weren't super productive, and also absorbed tons of time from other SE to get this person up to speed. Add in PM time bringing this person up to speed on our product.
Yup, $5k/week.
Clients on AWS were always my best ones, because they were used to paying so much over the odds I could set my rates much higher.
They didn't want to increase the head count. The AWS spend was a different silo/team/contract.
Corporate accounting is insane.
It almost smelled like "well, we negotiated this great AWS discount, so it doesn't bother us that we are spending an extra million. We're getting it at a DISCOUNT!"
Is there some MBA trend where every headcount is some ticking time bomb of liability that is 10x worse than their yearly salary?
You spend 150k on servers, they don't improve over a year.
You spend 150k on a decent employee, not even rockstar ninja 100xer, and they will deliver useful, although sometimes hidden, productivity and optimization.