Dude, all the work is in the maps, and they generally sell them proportional to the amount of map content. There are two benefits:

1. Studio doesn’t have to staff up to do all the content at once, but they still get paid periodically for what they do produce. This keeps the staff employed longer in a more stable position.

2. You can pick and choose which areas you want to get. If you want a big bundle, those still show up on Steam too at various levels of discount. But you’re not locked into having to deal with Ohio too.