Well for starters, web deployment isn't "everything". Python is the de-facto go-to language for research or general prototyping, where not everyone is a programming wiz keeping track of the latest trendy new compiled language. Not everyone can compile stuff even.. :)
Having said that, I've deployed two large Django projects on the web with tons of customers and it runs and scales just fine, and it's a DREAM to maintain and develop for than for example Java.. I would go so far as to say the opposite, if you haven't used Python for web deployment you've been missing out! (you lose some efficiency I'm sure but you gain other things)
I don't think that proves anything. If we had "JavaLisp" in the browser instead of JavaScript then Lisp would be very popular. Besides that, Python is harder to manipulate than many non-Lisps, such as JavaScript and Go.
Here, we can set Lisp aside and take grandparent comment's definition of syntax to be concrete, character-level syntax.
Python concrete syntax is harder to manipulate programmatically compared to Javascript concrete syntax.
For instance, to insert one statement into another, we need to traverse the lines of that syntax and add the right amount of indentation. We can't just plant the syntax into the desired spot and be done with it.
Native library interfacing isn't really Python's strong suit, interpreter plugins are quite painful to write.
.NET has P/Invoke which is much nicer.
JVM is getting Panama+jextract, which is the nicest yet. You can go straight from header files to pure Java bindings which don't need any extra native code at all. But it's not shipped yet :(
A few years have passed since I last tried out both languages. Ocaml was sort of approachable, while Haskell required quite a different mindset imho, hence the “nicheness” from the general usage standpoint.
Huh? Why?
You can barely deploy it to Web.
it doesn't scale perfoance wise
you can't built robust abstractions
The REPL is merely OK
You can barely ship working code without containers
the syntax is hard to manipulate programmatically
Python has inertia but it's holding us back