The example which author provides does not strike me as a great illustration for this point though.

> “Hey, I think we should experiment with Kotlin. It has lots of traction, Google officially supports it on Android and seems might help us write better code. Here is a PR showing how it’ll fit into our project.”

> “Umm, engineers will need to learn a new language. We have other priorities right now. Let’s consider it later.”

Without knowing too much of details, this looks like it can be a very valid point against introducing new language or technology when you truly have higher priorities and current choice of languages is good enough.