I currently design new products for an established company. When I finish a product, there's a trained staff of production, sales and support people that make the product successful. (Just speculating but) it's quite possible that the Heroku folks think they can't grow as fast without some additional business infrastructure. If this accelerates their trajectory, then they'll quickly get some distance between themselves and the zoo of other (not as slick) app hosting platforms. Just having someone else to take care of the legal side of HR so that you can go back to product development, while at the same time putting enough in the bank to live on the beach forever, may have looked attractive. Lots of possibilities, but a billion dollar cash-out is not the only way to make yourself happy in life.
