What is a good question to put at the end of a debate for gambling?
You'll NEVER "put an end" to a debate about gambling; or for that matter, to ANY debate.
That being said, a relevant question or issue might be about the mathematical expectation - a term which I encourage you to look up, if you are not familiar with it.
Governments, or gambling houses, organize lotteries, etc. for a profit - and since they don't generate any ADDITIONAL money, but only redistribute existing money, it stands to reason that the clients will lose, on average. That is, their mathematical expectation (average earnings, minus the price of the ticket) is negative.