"...he only has one ecosystem to work with and it works well."

Unix is one ecosystem that works well, too.

In my case, we started a web dev company using Microsoft tools I got from my brother-in-law who managed a large Microsoft shop. After a year, Microsoft made changes which totally crashed the most important parts of our project (long story) to where my brother-in-law told us we should switch to Linux. We actually wound up with FreeBSD but now use it exclusively for 10 years.