I agree with the part that says [Domains have and will continue to go up in value] to a certain extent.
The part that reads [faster than any other commodity ever known to man] is something I would rather not comment on. This part of the statement is much too bold for a professional to make (more suited for someone who's in the "medium" or "fortune teller" industry).
Unfortunately, the currencies we use and the market for these digital assets are both susceptible to economic factors (eg. recessions) which indirectly affects the demand, speed and frequency at which investments are made in the domain industry. So thinking (continuously) in the short-term, I disagree because it's an impossibilty.
However, like real estate property, even though there are downturns in the economy, it continues to grow in value over the long-term. So in the case of "digital property", there's hardly much difference.
IMO, technically the statement (whomever said it first) is inaccurate - but on a broader scale (like with actual real estate) the long-term value of Domain (Names) will always be on the up.
BTW: great referral-link to use when educating end-users/buyers about the value of a domain, and why it's worth investing in.