However, using a blanket statement to characterise the potential of a startup might not be the best way forward. From what the author says, it would be impossible to see Twitter, Foursquare, Square ever be born. I for one would not be happy if they did not exist.
Just because one has never seen an idea getting successful might not always mean it is impossible. It often means no one has tried hard enough. I know the pragmatists would thrash me by saying the contrary.
The truth is that there are many ways to go about founding a company. One is to actually set off to found one because to you the joy of founding and working for yourself while solving a real pain is what is of prime importance. The idea or the sector you are in might not be the closest thing to your heart. (Though it must not be too distant too). This is the way that Paras speaks of and for most of the folks it is great.
Another way is to just work on something that solves a real problem for you. It might be just a simple app that tells you all the cool places in a city maybe just your city but something that you want to do and feel there is a real need for. A point to be noted is that by now you have not thought of how it will make money or how the server bills will be paid. Well do not worry you are not the first person to go this way nor the last one.
The other route is to just come up with a crazy idea that everyone who hears has just one thing to say: "Why won't I use this with that or why do I need that". Don't worry if others cannot see what you clearly see. In such a case the final product is already in your head and you can see hundreds of uses for this. Every day you refine it in your head till the reality and vision of the product converge. Chances are that if you actually stayed around to see them converge then you have something going on for you. Either you actually believe in the product and it is a great product that the world did not see the need for till they started using it OR you were just being delusional. I would say the chances of being delusional if you stuck around till a final MVP are not very high.
Each of the above 3 paths are for different types of people. So before you follow any advise as a rulebook, step back and do some soul searching. You already know what way to go for.