Somewhat poor people?? It's estimated that 90% of Americans take the standard deduction and, my bet is for the vast majority of those, it creates the lowest tax liability and is the correct choice. So again, all this talk about logs is moot. For most people you're paying tax on the W2G period!
And there's the rub...
I think we ultimately get to the point that it's nearly impossible to fairly tax winning gamblers. And then the vast majority of gamblers, who are overall losers, are going to pay increased taxes on invalid income. It's a F****d situation.