Quote from FMPONEI think this is a real consideration. Can anyone name any game other than UT4 (not even released) which uses UE4? Whatever you make isn't going to be played in all likelihood, and that's hardly ideal IMO. Levels are meant to be played, not hung up on a wall somewhere.
Well the cycle is:
1. A new engine is developed, usually, around a highly acclaimed game. (Top engines are rarely developed around no game at all)
2. Game has mod support and a community.
3. Point 1 and 2 germinate interest in the engine.
4. Everyone develops games for that tech and it becomes popular based on how popular one of the engines leading games has become.
So, if UT4 becomes super popular, it will garner huge interest from all corners of the world. That's my 2 cents on this. It's also why I view UE4/UT4 as a very important career stepping stone for anyone both employed and unemployed. Its very likely UT4 will have a large following.