This article's title is misleading, it should read more like "...Don't do it for the wrong reasons" as he explains in the actual post. Beyond these reasons there are tons of people who want to make a company because:

- They will offer something novel or fresh

- They have the passion to change an industry that has otherwise been stagnant

- They want to offer choice or competition for a product that has been relatively monopolized

- And to a smaller degree if they're outside of the NYC/SF area, bring the tech scene to other areas of the world