People have finite time and not all communities are blessed with people who basically work full-time on those things. PureScript doesn’t have a big enough community to attack several of these fronts at once, being that there aren’t enough people familiar enough with the compiler to work on these things.
If the direction was somehow the other way around and expressive power had been neglected in favor of optimization I personally would simply not use PureScript, because I’m here for the expressive power and the largely unparalleled opportunities for abstraction. Someone can fix the optimization bit later, but when a language is established it’s extremely hard to actually add meaningful features with regards to abstraction.
There are languages that have been trying to add type classes (or some analog of it) for many years at this point but at best they get some neutered version of it or it simply vaporware.
I actually think in the general case is where it simply doesn’t.
It bears keeping in mind that projects like buckle script haven’t added any meaningful features to a language, they’ve simply chosen to translate code into another. Optimization, at that point, is basically the task.
PureScript is a new language with evolving features and significantly more features, so it’s not really a great comparison in terms of projects. Even more so when you take into account the relative size of the communities.