I'm kind of surprised Buddhism hasn't gotten more popular in the west, considering Siddhārtha Buddha's story sounds like what a lot of people (especially those from wealthy countries or backgrounds) who
are going through depression and the dissatsification with modern life complain of.

I wonder if it never became widespread in the west is because it's too exotic in its supernatural element, because there's no middle-ground between lay life and asceticism or perhaps because a lot of its teachings are categorized or described with very complex and foreign-sounding words that a lot of westerners find it hard to get into teachings or are mystified by the Theravādas and your Mahāyānas.

I don't know, I thought it would be more popular by now considering most peoples beef with religion is the Abrahamic teachings not approving of homosexuality. (Which I'm aware is controversial itself in Dharmic religion, but the exotic and progressive marketing that a lot of temples do to attract westerners would omit this.)