I'm not so sure that this is true, but I do agree that as of this moment it is so.
The key thing you are looking at is (capital goods at time 1 / currency at time 1 ) / (capital goods at time 2 / currency at time 2).
Under a gold standard, mostly this means deflation with some periods during a gold rush rapidly going the other way. It becomes better to hoard gold and do nothing, and as you hoard the value rises further. This leads to economic stagnation because we don't actually encourage innovation.
Under a Fiat currency scheme, the reverse happens. The value of the currency is constantly dropping. So what you see is people hoarding capital goods. What makes this worse is that we are incorrectly treating land as a capital good. So this is what we see today, people buy shares or land, that value appreciates as the money is printed, and they earned nothing. And as people learn of this, we get crazy things like 401k's that invest in everything in order to grab a piece of this appreciation. We get crazy things like companies taking out bonds, then using those bonds to buy their stock, never actually using it to become more productive, because productivity doesn't pay. More economic stagnation.
If this rate is changing over time, we get speculation. We get rent-seeking. But if we were to introduce a system that forced this rate to never change, we could get through. Of course, the leading power would never allow that, because it's the leading power that is speculating on the assets that are appreciating.