Yes, that's true that support at the right time would be much better than leaving it till crisis point. However, many people stay a little overweight without going on to becoming obese.
As we were just discussing, I actually think that "nipping it in the bud" if that can be interpreted by some to mean "quick, lose weight as fast as possible; then just keep it off" can be counterproductive for the reasons we've mentioned already.
So, there is a balance to be struck I think.
Support could mean better access to nutritious food, less promotion of fad diets, better access to gyms. Walking is free, but it takes time. The other issue is lack of childcare for parents of young children, particularly single parents. It is very difficult to exercise efficiently with kids. Walks tend to be shorter and slower for example. Also addressing MH issues early on, so people don't end up in a position where all they have is food to sooth their emotions.
Anyway, my point is that support costs money. This is why it is reserved for people in absolute dire need. This is the problem, not just for weight, but general health too.
Not everyone needs support, but many do. But I don't see how that will change any time soon, sadly.
One thing which categorically doesn't help imo, is being overly critical and obsessing over BMI. Healthy changes are easy to put into action, but if you are only concerned about your dress size and the scales, you will quickly become disheartened. This is why get thin quick diets are so popular, but, as already discussed, they may actually lead to people becoming even fatter in the long run. If people were encouraged to make the changes and stick with them, they would find that weight would come down in time. But it's the "in time" part which is problematic for many; "why aren't I / you thin yet? Why aren't I / you losing weight"? But actually, I think that is the worst possible approach.