I agree with you that being comfortable with a stack is not a good reason to use it. Developers need to keep up with emerging languages. Team leads also need to

I agree with you that being comfortable with a stack is not a good reason to use it. Developers need to keep up with emerging languages. Team leads also need to be doing this and provide direction. But as I said, there is more to the success of a project that the language and I think people get hung up on this. Yes look at all the options, but agree on a language/stack and move on. Also, give just a tiny thought as to whether you will be able to hire any developers to support the thing in 3 years. Boring yes, but kind of useful.