Even if it selects for that trait, it doesn't mean that there isn't a significant level of cheating. You can reduce the incidence of X and still have problematic levels of X.
Edit: An example: the US homicide rate has fallen in recent years. That's good news. But the US still has a serious problem with homicide, as its homicide rate is an outlier at 4-5 times that of all other first-world nations. Americans are getting less murderous, but murder is still a serious problem there.
Edit: An example: the US homicide rate has fallen in recent years. That's good news. But the US still has a serious problem with homicide, as its homicide rate is an outlier at 4-5 times that of all other first-world nations. Americans are getting less murderous, but murder is still a serious problem there.