Who said to hang on every word? You asked yourself who he was. He is someone who has done a few things right to say the least.
If you discount all past entrepreneurs simply because you chalk it up to them all being lucky to "get in early" I think you're missing out on the point.
Some individuals have a knack for looking at things in a different way. Some are able to put luck on their side many times because of preparation and foresight.
I would never change my business plans because of what one person is saying. But at the same time, to flip over the blinders and not listen to other opinions is a sure way to limit your potential in my opinion.
*Also, as an investor I know that Mark Cuban is not always right. He's invested in some companies that have languished or continue to languish.
http://news.earthweb.com/bus-news/article.php/3376981 http://www.bizjournals.com/stlouis/s...1/daily90.html