This. Why chase the latest fad while you can spend that time on working on the product? The workarounds for the issues that the proven solution has are well-known, and learning them is a sunk cost. The issues of the new platforms are yet to be found, maybe you need to fix them yourself, maybe the issues are different and you can fix it with different architecture.
Probably because by the time they've transitioned to the more popular language, an entirely new programming language will be the one more great programmers want to use.