The majority of courses on Udemy are priced at $199.99 and "on sale" for under $20 almost permanently (even though the sale says it's temporary). I can see how this might make people think they're getting a good deal or make a purchase because of FOMO, but with the extent they do this it's kind of obvious that the deals aren't legitimate or limited and might damage their brand image. But regardless of the pros and cons, I find it very interesting that Udemy has been doing this to such an extreme degree for many years while I don't see any other online sales sites like Coursera or Amazon doing it much.

Is there any research on whether this is actually effective? If it is, why doesn't every company always have everything on sale for 90% with a high fake original price?

Or if it's not generally effective, why is Udemy doing this?