Hey, so hum, this is a game in progress and you knew it, so it was bound to not be finished. I wouldn't say it's short. It's more likelly that you just have lot's of time to play this in one go.
Before chosing to spend your money you can play a good portion of the game and you have the dates in which the updates were released. So you'll know the usual interval of time taken to have an update. Nothing is hidden, and you're not being taken advantage. This is you being a little paranoid. If you suspect a creator has abandoned the game, just look for the latest interaction with the players.