[supercat]

As I see it, a major problem with the 'reusable vehicle' concept is that while a pound of 'stuff' that doesn't have to be recoverable adds a pound of spaceborne weight, a pound of stuff that does have to be recoverable adds considerably more. Since every pound of spaceborne weight adds well over a pound of launch weight (since it requires the addition of more fuel to get aloft, which in turn requires more fuel, etc.) adding the extra shielding etc. to make a vehicle reusable adds enormously to the amount of fuel that's required to get it aloft on each and every flight.

[NonZeroSum]

I think that if you actually run the numbers, this logic fails. It's still cheaper to recover hardware than to throw it away, if the flight rate is high enough. If the flight rate is low, it's not worth developing anything new.