Cargo-cultism is the duplication of the appearance of functioning systems or structures in a context where they are nonfunctional or incorrectly functional. Cop

Cargo-cultism is the duplication of the appearance of functioning systems or structures in a context where they are nonfunctional or incorrectly functional. Copying the functionality of an existing system isn't a cargo cult. The persistence of features in programming languages you're describing isn't a cargo cult because the resulting products work. In addition, there's several benefits of conservative language development: it's generally easier to write compilers; existing programmers will find it easier to adopt a language that mostly resembles ones they already know; and some unfashionable but useful features may be retained. This is more of a "worse is better" situation than a "cargo cult" one.