I think that most people, including leads, they do see the benefits, but they think the cons heavily outweighting the pros.
Without having a certain number of key developers pushing the transition it's hard to make this jump.
I would also say that this kind of transition can be had progressively, I myself know a person who pushed a company into a fully-typed static pure functional programming a team that started their whole business in php. Gradually moved them into typed functional php and then into Haskell. He was lucky enough that the team/company was small enough for that at a bigger scale this would've been much more difficult.
In other places I've seen the transition happen (into the functional typescript ecosystem which is a sweet spot imho) it has been mostly the CTO pushing for it.
How do you gradually move the software of a small company to Haskell? Do you have to build two artifacts, one in PHP and one in Haskell? Two deployment mechanisms?
I don't know the specific details of how the transition went exactly, I didn't work there.
I know they moved into a more functional php, then typed php, then started rewriting some parts of the system to Haskell. The company got eventually bought up by a competitor and killed.
Few companies I know here in Italy are going through a similar into more functional and statically typed php with efforts such as facile.it with libraries like that:
Most go through the fp-ts/effect-ts ecosystems and never jump on the scala/haskell languages as they find functional typescript to be the sweet spot for them.
Without having a certain number of key developers pushing the transition it's hard to make this jump.
I would also say that this kind of transition can be had progressively, I myself know a person who pushed a company into a fully-typed static pure functional programming a team that started their whole business in php. Gradually moved them into typed functional php and then into Haskell. He was lucky enough that the team/company was small enough for that at a bigger scale this would've been much more difficult.
In other places I've seen the transition happen (into the functional typescript ecosystem which is a sweet spot imho) it has been mostly the CTO pushing for it.