Who's to blame for that, I guess it is not the progressing technology should be blame, instead blames are all to the parents or guardians for failure to do their job in monitoring their kids.
Nonsense. You can't control and monitor kids 24 hours/day 7 days week, that would make you bad parent and kids will probably hate you. You can guide them and teach them what is good and what is bad. It's only up to them if they want to take advice and guidelines or not.
I wonder if monitoring Kids make us a bad parent. It seems in your case, it is bad parenthood. So what is good parenthood then? Letting kids do their own things? There is an ordinance in my country where parents were the one to be punished once their kids were caught roaming around the street after curfew hours. This only mean that this kids are parents responsibility. Sometime parents need to punish kids or ground them or even monitor them to make sure these kids are growing according to the value they wanted this kids to learn. So being responsible parents, we should implement stuff that our kids will take our advice because it is for their own good but not to the point of abusing their rights.
As for the online gambling, we can setup limiter in our pc's so that minors won't have access to gambling sites . It is better than monitoring them 24/7 while they are using pc.