In Singapore they have real rules and real consequences for breaking those rules and I wonder if that is part of the reason why Singapore is vastly more successful than all the surrounding nations all of which are significantly larger, have natural resources and a much higher population. I can't really speak for any country other than the one that I live in but there are no smoking SIGNS all over the place and then people smoking right in front of them. It's just like the speed limit signs that everyone ignores. If there are no consequences for breaking a rule, what point is there in having the rule?
People smoke wherever they feel like it here and then discard the butt on the pavement when they are done. It's kind of upsetting as a non smoker.
It is the reason why Singapore is different from the other countries in the region. There's no other way. As you say, why have rules if no one cares, not even those who should supervise respecting them. Once you strengthen control and fine those who don't want to understand, you'll get results.
The problem stems from education or the lack of it, to be precise. It's a no brainer not to throw the butt on the ground, if you want a clean environment. It's sad people don't realize what is at stake.