Can wikipedia really stay impartial?

I was recently reading an article about a business where for $50 this dude would write and submit a description of your business to wikipedia for you. When Wikipedia found out about this they yanked his posts. Is there really an issue here? Isn't it safe to say that many of the posts on Wikipedia are self-serving in some manner or another? Isn't the purpose of the review team to root out corporate promotion for the sake of promotion? So if these post passed muster and made it to the site originally shouldn't they be good enough to stay there?