It's free and open source. If you increase the price that high, people wont see the point of buying it and supporting the developers. Either way, it was never made to make money...
You could. It's open source, so if you want to fix it yourself then do so. Also, it's completely free. Feel free to try it out and change some things yourself...
You can even sell the game yourself. It's less than a free game. You can technically sell the game yourself, yet you should probably make it your own. You would need to retain the licence as well.
