It's still going to be on the side of the parents/guardians to take care of their love ones, like what you said, if the country is free for types of business, there's no way that it can avoid to see ads about gambling to the point that it can direct viewers and followers to follow them in their journey towards gambling, there's no stopping as those kinds of business are bringing generated income for the government in terms of taxations especially those undergrounds transactions.
Even though we say that it was allowed in the country, the government still has control over it. The responsibility is not just for the parents but also on how the government sets rules in regard to advertising materials. And also, the schools will educate students about gambling, just for them to clarify things. Because some gamblers found gambling due to their curiosity, and this is likely to happen in kids.
But if the country is governed by corrupt officials, there is nothing to expect. Casinos will continue to feed them and be free to do what they want to do.