I can give you some pointers, as a relatively young lisp developer (came to it ±3 years ago): at the time, unappealing official website (now fixed); only books to learn, few online code-first resources, so was harder to learn than necessary (greatly improved); only Emacs & Vim first-class support (now we have very good Atom and VSCode plugins, and more (Jupyter kernel,…)); hard to find libraries (only Cliki existed, it's now better, and there are plenty of libraries); Quicklisp seemed limited from the outside (although it's great) (we now have Ultralisp and the CLPM package manager, along with Qlot (directory-local installations), utilities like Roswell etc); hard to know if the language was being used at all (we now have lisp-lang.org showing success stories, awesome-lisp-companies shows more examples); hard to get into web development / no major framework (the Cookbook helps and there are many choices, although still no world-class framework. But I use a Lisp backend, classical Django-like templates and it's enough to build real-world, work-related stuff); no good GUI options (there was Qt4 without much examples, and Ltk. We now have IUP bindings, some more, and a Qt5 is coming soon©);…

Others know better the limitations of Lisp systems of the 80s or 90s. The compilers also improved (SBCL; there is CLASP in development to interface with C++ code, and more)

TLDR; it's catching up :D