If your devops is inadequate, so that you have low visibility into your product's performance, can't degrade gracefully, and have trouble deploying things without significant downtime, investing in proper devops infrastructure and processes may directly help your bottom line.
The set of companies that have any sort of reliability or performance-oriented need a "microservice architecture" is three, maybe four orders of magnitude smaller than the set of companies building web applications. They--and you--have been sold on a trend that is actively antithetical to the goals of delivering a product.
Build your application. Use an auto-scaling group and an ELB. You have more important things to do until you reach the scale where you can pay someone (hi) to do them.
I think most of your points are valid (wherever my experience is enough to judge).
A pre-requisite to "spend as much energy as possible on end user features" is to have some sort of foundation to build on that can grow with your platform, or you might as well build on quicksand.