The USD broke through the 1.20 barrier briefly yesterday, before recovering to close slightly above 1.20.
The fall in the USD has been relentless as it was trading at around the 1.30 level at the start of the year.
Those who have invested into USD denominated assets would have to earn a return that is in excess of this currency depreciation before they can see any return on their money.
The currencies market tend to be a very long term trending market in nature with bouts of short term volatility. Trying to bet against a long term trend can be quite sucidal, as losses will pile up higher and higher.
This applies especially to those who have bought into certain currencies at a higher price and want to wait for a pullback into their purchase price before they sell their currencies.
Remember, that day might never come. Just look at the 30-year chart price chart of GBP/SGD as one good example.