I was never much of a Forex Trader but I know some people who are and they told me. Just by looking at the currency charts of the last 15 years and the VIX I can easily support this €/USD for example has been a good ride between 2002-2009, but since then its been way harder to make money trading these.
Hard to believe making money from trading forex has ever been easy. Blaming reduced VIX for reduced gains doesn't seem like the full picture - like blaming the dry weather for the lack of rain. Unless they were trading the VIX.