It's not that those languages are "lisps", they just mostly use s-expressions. That's because the syntax isn't what they're trying to innovate on, or what the

It's not that those languages are "lisps", they just mostly use s-expressions. That's because the syntax isn't what they're trying to innovate on, or what they're trying to stand out with. And also because once you understand s-expressions, it becomes kind of hard to justify not using s-expressions. Honestly, why bother with novel syntax when your PL semantics can be expressed in terms of s-expressions?