The difference between chalk and cheese
Samsung have very little to gain or lose from their Android competition. There are countless apps for the Android platform that will run quite happily on the Galaxy so it doesn't really make much difference whether anyone enters the competition or not. Writing an app for the Galaxy is no different to writing one for any other Android based phone.
Bada is a different kettle of fish altogether. Its entirely propitiatory. Bada apps run only on Samsung Bada phones. Unless Samsung can convince mobile developers to learn Bada (as well as Android, iPhone, Pre and Symbian) then Bada is a dead duck. They have to overcome the Bada "catch 22". There is no point in developing for Bada because there is nobody to buy may app but nobody will buy Bada phones because there are no apps for it.
To be honest I would think the Android competition is more generous than the Bada one. As an existing Android developer it costs little time and effort to have a punt at the £2k, but would take a *lot* of time and effort to tool up, learn Bada and create an app for a platform that stands a good chance of flopping on the outside chance of winning £300k (or less). If you have a great idea for a "killer" app, then its far better to develop for the mature Android and/or iPhone and be fairly sure of making money than taking a long shot at a winning a prize.