Re: "he expected demand to be so great"
This time last year, apparently around 8,000 people had put down deposits for a VG flight, and in recent articles, a figure of 600 has been quoted of people who've actually bought tickets so far.
The new VSS Imagine ship (the first SpaceShip III class ship), seats 6 passengers, VG plans to build a 2nd one of these (no dates yet as far as I know).
They have stated they plan do about 400 flights per year (eventually), although I assume they at least need the 2nd ship for this, and will likely start much slower.
So you're probably looking at at least a year or two to clear those initial 600 ticket holders, then an additional 3+ years for the ~8000 deposit holders, assuming they manage to ramp up to the proposed 400 flights of course. (and that all 8,000 actually go through with it of course).
And that's with static numbers, presumably ticket sales will kick off again once flights are going. I also suspect many people who are interested in a flight, likely want to wait a while for the tech to prove itself, so won't have put down a deposit yet.
Assuming they achieve and stick to 400 flights a year, and the 6 seat configuration, that's 2,400 people each year buying a ticket to sustain those flight numbers. The US alone produces over 600k new millionaires per year, so there's no shortage of people who are going to be able to afford it.