How much revenue you can generate per developer is totally irrelevant. If you generate millions in revenue but server costs eats it all up, paying a 3x+ premium to run on AWS can easily bankrupt you. By all means, if your server costs are inconsequential to your bottom line, go nuts.

I've just moved a client off EC2 because the premium they were paying would have been a massive problem. The 85% reduction in hosting cost has bought them months of extra runway. Their operational costs related to their hosting also dropped - there's simply been fewer issues to deal with.

I'm sure there are instances where AWS is fine. But there are also plenty of cases where it is a matter of survival to cut those costs.