What are the cons of Lisp?

Lisp's biggest practical drawbacks are its unfamiliar parenthesized syntax, a much smaller library ecosystem than Python or JavaScript, and a small pool of experienced developers, since Lisp has remained a niche language since its 1958 origin even as it shaped functional programming features used elsewhere today.

What do these drawbacks mean in practice?

The S-expression syntax, with its heavy use of nested parentheses, takes longer to read for developers coming from C-family languages, even though it is what enables Lisp's macro system in the first place. The smaller ecosystem means teams often build or adapt tooling themselves rather than pulling a ready-made library off the shelf, and a smaller hiring pool makes it harder to scale a team quickly compared with mainstream languages.

Where do these tradeoffs matter least?

These drawbacks matter less in research, symbolic AI, and specialized domain-specific tooling, the areas Lisp was originally built for at MIT and where teams already accept a smaller ecosystem in exchange for the language's flexibility. They matter more in general application development, where mainstream languages offer faster hiring and broader library support.

What's the practical takeaway?

Weigh Lisp's cons against what the project actually needs: if the work requires custom symbolic logic or macro-driven abstractions, the syntax and ecosystem tradeoffs are usually worth it. For general-purpose software with tight deadlines and standard requirements, the smaller talent pool and thinner library support are harder to justify.