What other tradeoff targets would be the considered as sharing python's expressiveness and conciseness? One of the python variants like stackless? C?
I'd be very curious as to the answer here. Some times you do like the pretty code from something like Python, but you get backed into a performance corner, at least I could see that happening.
I don't even think it's about pretty code - I think it's more related to what one sibling of the post you replied to mentioned, which is that there are tons of communities (among them machine learning, but including tons of stats-heavy academic programming) which would REALLY like to do some extremely heavy work in Python, not because it's necessarily the best, but because it's what they know. Academics in particular (not CS academics, but stats and experimental sciences people) can be forgiven for wanting to stick with Python - they aren't programmers, they don't want to waste time learning programming language skills that are largely irrelevant to their job. All they want is to pick up an easy language and be able to do their work in it, but once their work gets heavy, the language starts to fight them. And that's a really popular use case for Python, I think.
That is the real problem. Any sufficiently popular language will inevitably be used in scenarios it is not suited for. Python has now reached that threshold, so all sorts of communities are trying to stretch it and pull it every other way. Sometimes this makes the language better, sometimes it's just a source of complication and frustration.
There is also the issue that some quarters feel python's role is being eroded by newer stuff like golang and nodejs, which were built with high-performance multithreading in mind from the start. I personally think this is not much of a concern (if you are willing to trade python for golang or nodejs, you were not really using python because of its expressiveness and conciseness in the first place), but clearly a lot of people do.