Language choice had less impact than people first assume even before LLMs in most software. A good engineering team produces good code in whatever language they happen to be using. In my own career I've worked in serious Java, Scala, Haskell, Javascript, PHP, and Python application stacks and I've seen plenty of good and bad examples.

I reckon language choice matters more at the edges of economic activity where a specific language feature really does make the difference in the end product, but most activity that is leveraging LLMs now is more generic enterprise SaaS software.