It is easy to be a critic of private venture backed companies valuations as these investments are done considering where the world could be in the future vs where it is now. These kind of bets requires not only financial models but also unique vision and a lot of guts -- traits hard to train but present in most of mankind's big achievements. So it's no wonder those bets pays really well when they succeed.

Of course, if you're not a fan of how the private venture backed companies game works, you can always do a traditional business and use profits as the only source of growth. That's the beauty of our current system: it's not perfect but it still allows you to choose whatever path you want to and still have a good chance to make it work.