Depends on the artist.
Tech dropped an EP in the summer, then turned around and dropped that Whoo Kid mixtape in December, and is writing now for his album in June.
It's not an excuse as far as cutting back to save embarrassment for a bad product.
He buys his beats in bulk, so only buying what he wants for an EP to cut cost doesn't make sense either.
He's not under contractual obligations to get out of a contract, so making it for the sake of having a UPC stamped on it and marking it off the "only a few more to get off this label" list doesn't make sense either.
He did it solely to capitalize off of the K.O.D. album and to appease his fans until his next project.
I can see how it would be a money saver to do it, but everyone has their own reason for doing it.