[ndefinite]

From an economic standpoint it's not inflation you need to factor in it's the reduction in cost of production over 500 years (assuming away any issues with the time scale the author presents). Also known as deflation which is in fact a good thing (sorry Chicago School, more for less is a good thing).

Over time advances in technology and increases in capital (capital defined as production goods here not cash) tend to dramatically reduce the cost of production.

Not to mention the insane decrease in the cost of raw materials once you start collecting from asteroids (again assuming we're 500 years out and can build a moon sized ship we can certainly snag an asteroid or two for materials).

[openyogurt]

Right. I thought it odd that the price of steel and labor would remain constant for 500 years.