“It is not about ideas. It is about making ideas happen».
— S. Belsky, «Behance» founder.

Ideally realized startup requires absolute knowledge of your product, target audience and the methods of monetization.
If something about those is wrong, startup, eventually, will fail.
Sometimes, entrepreneurs are too optimistic on easiness customers gaining, so they think the product is ready to prosper their business even on a stage of «pure idea».
When the startup isn’t ready, they start to attract attention too early, run out of money and fail.

Another scenario is the team is busy with too many features of the product, but not the large target audience. The thing is, it looks like they make it more for themselves, but not the large market. This is why there might be not enough value proposition to make the buyer shout «Shut up and take my money!».
When a company is ready to present its Creature, they try to sell it and fail, and the reason is lack of market research.

Another thing with the product features is when you focus on it’s present pros and have no long term vision. If you don’t have a detailed plan where you are taking your company through years and what all of this will grow up to, then it is impossible to convince іnvestors, partners and other top managers. Sad, but true.
It is not about the aim, it’s all about the system and strong strategy or a business plan, flexible to the fast-changing market needs.

And the last, but not least issue is poorly organized team. Well managed would not let the fail happen, being a perfect puzzle, where all the details are in it’s needed place.

All those factors can make a hole in your pocket instead of making it full with gratitude of happy audience, their cash and global recognition.