Let me ask you a question.
You spend hours and hours developing a game, all those hours of developing are backbreaking (not literally) labor. You used up all that time of your life to develop it and make it cost money. Now, you begin to get a steady income. Not only that but this is your only job, you don't work anywhere else. If you were to make it free what would happen?
Badspot would lose his house.
Badspot would lose the master server.
Badspot would be a homeless.
There would be no more support for blockland.
No updates, no forums.
No website, how will people learn more about the game?
Upon losing the master server, there would be no more blockland as well.
Considering all the side effects I think you're right.
Badspot should make it free.
But what am I saying, you're just a 7 year old that can't mow lawns because he's overweight.