I think you'd get more interesting answers if the question were asked like this: Why do people discuss the relative merits of programming languages instead of spending that time learning a new one?

As currently stated, it's loaded with presuppositions that are hard to overcome if you want real answers. (eg: This post is language advocacy, language advocacy is a waste of time.)

Why is it so important to learn new languages all the time? Wouldn't you rather just get your startup going as quickly as possible?

The implementation is not inherently interesting. It's just a means to an end.

"The implementation is not inherently interesting. It's just a means to an end."

If no one on your team finds implementation details inherently interesting, your implementation is likely to suffer, perhaps to the point of being uncompetitive.