That is my personal experience, a tiny data point, again where are the studies that give some actual useful guidance?

I wrote a great project using Racket, everyone should use Racket, its cool, lets blog it ... gains momentum, its new its exciting it promises change ... people start to have different experiance, bad decisions are made ... new bandwagon, lets all rush to that yay. Having been around for long enough to see this cycle, I think it's right to ask for some well thought evidence, or gathering of trade offs to help decision making.

My question is simple as that, yet as engineers we get lost in the detail of the doing and some hand wavy suggestion that it makes things better, yet where is the actual evidence for this?

Be pro FP or not, or any other programming paradigm, lets say logic based (prolog etc), where is there any measures on how it benefits outcome.

I appreciate this isn't something that can be easily measured, but that is arguably a key problem with the state of the industry, that its emotion, intuition and bandwagon driven.