I think that policymakers are more inclined to invest in curative aspects rather than prevention, is due to its lack of political appeal.

Preventive policies are more likely to show results over long periods of time, particularly for chronic diseases, which makes them politically unattractive for a policymaker seeking reelection. Investments in curative aspects are more attractive to the general population as well, especially in developing countries, who are not fully aware of the prevention effectiveness in reducing epidemiological burdens with remarkable cost-effectiveness. In short, from a public policymaker perspective, it is more appealing to say "I have built hospitals during my term" which everybody could see, rather than saying "I have invested millions in prevention" which nobody can see.

I agree that prevention of disease is more valuable comparing with treatment of existing diseases

Yea, @ Marianne, why not people failing to practice it?

I think its can caused by many society and policemaker that already think and focus on curative better than promotive and preventive.

lack of cost-effectiveness studies