Laziness most of the time is main problem. However, if you bypass that, add little character and effort - no way you can earn no money. At least as a side income, if not full time.
@Andreon Many are not capable to gain that skill because they are lazy/stupid or simply have no patience and can't understand that reality is not about "magical" programs teaching you how to earn 500$/ day ...
Sure, just buy my ebook and I'll show you how to make hundreds of dollars each day. Isn't that the claim the IM "gurus" make every day?
Right now, we're in the green - but some of our websites aren't because they were down for a few months, and now we're working on driving the traffic back, and boasting our community.
Isn't one of the big answers to the O.P. that there are 2 billion other laptop/computer users who are your potential competition. Standing out from the crowd is a biggy for ANY small business.
As said before one of the reasons is because people are too lazy, everyday we see new threads at DP asking how to become millionaire in a short time, how to earn easy money. Unfortunately most of people want to earn money fast with no efforts and with zero investments.
I could seriously write a whole book on why most people in this forum will never be successful within business, but fortunately I'm not in the business of putting people down. I'm also a firm believer in learning from ones mistakes in life.
The thing is if people don't have much knowledge, can't spend money to buy books to learn or don't know the exact methods or steps then fails to make money. Or if they have enough knowledge they don't take action and become lazy. Although now a days, there is too much information available which you can say is over loaded and people can't decide what to do and what not to do. These are the reasons which leads people to fail to make money.