I understand where your coming from. For me, the selling point of Dylan is that it gives me many of the things I like from dynamic languages, like Ruby, but also gives me static typing (and type inference), relatively high performance and a compiler that catches a lot of problems before I run my code.
Different people like different things, and while I love Ruby, static typing does catch a lot of problems earlier on.
But what does it bring to the table compared to other typed languages with dynamic features (or the other way around, e.g. TypedClojure, TypeScript...) and bigger ecosystems?
I'm not familiar with TypedClojure or TypeScript, so I feel unqualified to answer your question. I'll attempt to answer anyway, because this is the Internet.
At first glance they seem like subsets/dialects of other languages, which would reduce the benefits they get from their "parent" ecosystem? Similar to JRuby and Java, where I always felt a reluctance to interact with the Java side.
That said, Dylan has a pretty neat FFI, and it's simple to wrap C libraries into Dylan-looking interfaces, so at least for me it benefits a lot from the plethora of C libraries out there.
(I realize FFI is available to almost all languages, and doesn't really mean libraries are available to Dylan, but I find it very comfortable to bridge C and Dylan through its FFI.)
Different people like different things, and while I love Ruby, static typing does catch a lot of problems earlier on.