It's a strange upside down world we live in.. Domain name monetization has been going on in much the same way since adult webmasters began selling monthly memberships to porn sites in 1995 (3 years after the birth of the modern web browser) .. Today we have paid search monetization sites for virtually every product and service under the sun. Many are moving away from straight parking toward lead generation, arbitrage, content delivery and pay-per-unique implementations.
But these simple sites which for years have made money in the most benign of ways are 'bubbles' while the publicly listed internet economy, consisting of plates spinning on the ends of pool cues is accepted as foundationally sound and airtight.
All a fellow can do is smile, shrug and keep cashing those checks. It's too tiring and unproductive to pen a counterpoint to each person who don't understand.. or who doesn't want to understand.
Suffice it to say that the Internet has already crashed and burned once .. domain names did not experience that shock.. If there is a redux of 2000/2001 you can expect domain names to perform in a similar manner as before.
I'm not so sure all of Facebook's 15 Billion will come out the same way.