Businesses largely fail in first five years because they haven’t

Built a product or service people need: The trend today is Startups wait and watch an early adopter and then built an exact copy and try dividing the market share. Now there’s a big problem because they aren’t serving the customer’s needs but are looking for easy means for quick money. (Eg: Uberizing: term for startups who call themselves ‘ We are the uber of x’)
Built a product or service ahead of time: this is correlated with the earlier point but just to reiterate - The Technology was great the timing was bad. (Pets.com /Webvan.com/WebTV)
Built a great and relevant product but refused to adapt to changing trends: Some startups have built products after serious validation but they didn’t continue validating (TiVo, Pebble watch, MySpace)
safeguarded against Economic down cycles, disruption, lack of support from Goverment, investor fallout, cofounders fallout, team being poached are all other reasons why startups fail (Netscape, AltaVista, PalmPilot, AOL, Napster, Askme)
Scaled right to be just bought by someone and after too much of negotiation the valuations also decrease, these periods the founders lack focus on right things and soon it’s a downward spiral (SnapDeal, Zoomo, TinyOwl)