[7thaccount]

Probably because Matlab is basically an imperative scripting language with a bunch of array features bolted on. It's been pretty successful for numerous reasons although there is definitely a lot i dislike like the crazy high costs (you pay $$$ for the language environment, $$$ for the libraries that you want, and $$$ if you want to create a standalone executable). However, it's worth it to a lot of scientists for valid reasons.

APL is a lot cooler as a language, but is missing a lot of built-ins that Matlab has for numerical computing. The APL community would just tell you to write a few lines of code to implement what you need rather than call out to a massive black-box function. It's certainly a better approach if you have the time/ability, but I often don't. More recently, Dyalog Apl and Kdb+ (the two big commercial Apl or Apl-derived languages) have support to use Python libraries if you need that.