The spirit of attempting to reach a goal such as $1000/lb to orbit is measuring the money at some fixed date, say circa 1990. Obviouly the impact is the same to reach inflation adjusted equivalents. The same tradeoffs apply with the rest of the economy at that point. Any economic benefit studies of reaching $1000/lb to orbit in 1990 would probably be relevant for reaching $2000/lb today.

Ultimately, it is hard to communicate and compare these economic tradeoffs unless you use inflation adjusted numbers. And as a side note, if the cost to orbit would even stay flat against inflation, eventually the cost would be effectively quite low (inflation adjusted).