IMO there's no such thing as esoteric languages; it's just that some ideas catch on and some don't (or take longer). If C ideas had not caught on, today we'd all it an "esoteric" language.

Esolangs are not designed to catch on. They’re designed to be extremely difficult to use in creative ways.

This is missing the point entirely. Esoteric languages are those designed to intentionally be novel in some manner, and frequently allow impractical design choices to support the art, joke or boundary-pushing novelty. They're not intended to be used for day to day professional work.

Consider for example the Olympus language highlighted in the article. It is impractically verbose but is all the more amusing for it.

Other examples include languages made entirely from whitespace, one that I can't remember the name of that is designed to read like poetry in either German or English, and LOLCODE which is to be written in the style of lol cats memes.

Not sure if this is the one you meant, but https://esolangs.org/wiki/Shakespeare is relevant.