Good point. Is the amount of work that went into getting a successful sale worth a $400 profit? Keep in mind, this is providing speculative numbers for the sake of debate. The real world hours invested in gaining position or page rank, and time a agency would sit on a domain before a sale would be much higher. We interviewed a few agencies that practiced this, not only those that supported our theory.
There’s an important distinction to make here between domain flipping and website flipping. The latter mainly refers to buying and selling full websites. By full websites, I mean websites that actually have content and more often than not have traffic and revenue. When buying and selling websites, the domain name matters less as the main value there is the content, traffic, revenue, history/reputation, sustainability and growth opportunities. The same can’t be said for domain names where you’re just selling “the name” and hence it’s all that really matters.