The answer's probably a lot simpler than you think. Dropshipping is hot these days for the "I'm an internet entrepreneur" crowd and the "How To Dropship Guides for $19.99" are all pushing Facebook ads and buying from AliExpress. The readers likely don't even know that there are alternatives: they're just following a script.

The rapid churn when people realize it's harder to make money than it seems means that there is always a new set of people pushing whatever crap is hot that week.