mlochbaum parent
"already": APL dates back to about 1966, and even K from 1993 predates Numpy and Julia. But yes, we do not live in caves and are familiar with these languages. Klong has even been implemented in Numpy, see https://github.com/briangu/klongpy.
I understand that these languages are older; I meant that in the sense that they are nonetheless still trying to recruit new users, but these potential users may already be using something that does something similar.
Oddly enough, the biggest mistake in how I presented BQN early on was thinking only APL insiders would be interested, when in fact the APLers went back to APL and people who hadn't tried other array languages or hadn't gotten far with them were were most successful with BQN. Plenty of people coming to BQN have worked with Numpy or whatever, but I don't think this has the same deterrent effect; they see BQN as different enough to be worth learning. Julia in particular is very different: I don't find that it culturally emphasizes array programming at all.