I'm not making the case that gambling in and of itself is wrong...I'm making the case that gambling for monetary gain is wrong whether you can afford to lose it or not.
I don't think the analogy of drinking and gambling hold up. You can gamble without it being about money, but it becomes wrong when you gamble for money.
There is a biblical precedent for drinking, but not getting drunk. And there are biblical precedents for "casting lots" (if you want to call that gambling) but not casting lots for money.
I simply don't see this as an absolute as you do. Not all attempts to curry monetary advantage (even through "chance") are, by definition, "greed" or "coveting."
SD