Originally Posted by Gorath
The times are over. The 20 hours expansion pack was a child of the retail market. When retail presence was necessary to reach the customer you had to deliver a certain amount of content to make the box attractive at mid price.
Nowadays it's much easier to produce small pieces of content, call them DLC, bundle them into packs, sell a bundle of packs as season pass, create Digital Ultimate Deluxe GOTY Editions … and keep doing so for as long as the stuff sells or until the sequel comes.
Other positive effects are a probably much higher attach rate - who would buy the standard edition if he could get the GOTY with twice the perceived value for 2$ more -, far less risk (lower budget and no retail release!) and continuous media coverage for the different DLCs.
Only AAA games will still get the occasional expansion. It's worth doing if you can predict a 30% attach rate on a 5M+ installed base.