The more real answer is that python's primary usage is a glue language. It has to be able to interface with various C libraries, and to make the interfaces even

The more real answer is that python's primary usage is a glue language. It has to be able to interface with various C libraries, and to make the interfaces even more ergonomic, they exposed several internal details on how code is evaluated that libraries make use of (e.g. you can increment/decrement a ref counted python object's counter from C). This pretty much makes it impossible to change many of the internal details, and to significantly optimize it. If we remove this requirement, we get the alternative runtimes and if you check e.g. GraalPy, it has the same order of performance as JS, so your intuition is right. It's just that you have to drop supporting a good chunk of what people use Python for which is obviously a no go for most applications. (Note: GraalPy can actually also run some C libraries and in this case can cross-optimize across python and C!)