The single biggest reason why start-ups succeed | Bill Gross

1. The idea. However, the idea is not everything. 
2. The team and execution. Mike Tyson once said, "Everybody has a plan until they get punched in the face." Much about a team's execution is the ability to adapt and to get punched in the face by the customer.
3. The business model.
4. Funding. Some companies with intense funding don't succeed.
5. Timing. The idea is too early, and the world is not ready for it.

Aside from a good business model, a good idea and excellent execution, timing determines if a company succeeds or fails.

• Airbnb. People thought that no one would rent out a space in their home to a stranger. But the company came out during the recession when people needed extra money.
• Z.com (1999-2003) was an online entertainment company with a great idea. But broadband penetration was too low, and it was too hard to watch video content online.  In 2005,  Adobe Flash solved the codec problem, and broadband penetration reached 50 % in America, perfect for YouTube to start and become a success.