1. Massive online community
2. Virtual simulators
3. Part numbers and 2nd hand retail
4. Computer and phone interfaces
5. Patent expired so more community
This should probably read "competition". Some of the stuff secondary brands offer puts shame to Lego, both in creativity as well as in pricing. Bluebrix and Xingbao both have models that are a lot more playable than anything Lego has ever offered.
1. Massive online community
2. Virtual simulators
3. Part numbers and 2nd hand retail
4. Computer and phone interfaces
5. Patent expired so more community