I think something the scheme community could learn from Haskell is to lean-in on it's prestige. I see so many people post about how they were never able to figure out how to use scheme in any practical way, and most schemers I've spoke to said it took them about a year to get really compfortable. But I think the #scheme community has traditionally advertised it as "so easy, you can learn it in an afternoon!", and so people, often times already coming from some other #lisp like #clojure, expect to be able to just pick it up, and when they fail to they think the language is lacking. But nobody comes to #Haskell with such expectations, and the Haskell community never advertised it as super easy and quick to learn. In my experience, Haskell has always been sold as "takes time to learn, but is worth it".
@rml
If you were only interested in computers as a brute-force calculating tool, or interested only in the business side of #software, you aren't interested in #Lisp because it lost out to languages like Python, JavaScript, C/C++. So I think any Lisp will only attract people who are interested in lambda calculus and/or programming language theory, and/or maybe people interested in dependent typing, like anyone who has run across the work of Dan P. Friedman.
I assume it is not just me that the reason Scheme is appealing is because it is a well-designed minimal Lisp. And just being able to understand, from a pure computer science perspective, the deep philosophical implications of what a "well-designed, minimal Lisp" even means has already narrowed down the pool of potential converts to a tiny minority of people.
But the fragmentation is still the biggest problem. The absolute first question I had when I wanted to get started with #Scheme was, "which implementation should I use?" And immediately it becomes clear that once you have picked one, it isn't easy to just switch your code over to some other implementation in the case that later on you feel like the one you picked first is wrong. So there is soooo much pressure to pick the right implementation on your first try. That alone I think scares too many people away. I didn't run away because I was already committed to the idea mastering a "well-designed, minimal Lisp."
@rml
If you were only interested in computers as a brute-force calculating tool, or interested only in the business side of #software, you aren't interested in #Lisp because it lost out to languages like Python, JavaScript, C/C++. So I think any Lisp will only attract people who are interested in lambda calculus and/or programming language theory, and/or maybe people interested in dependent typing, like anyone who has run across the work of Dan P. Friedman.