Bad habit are why many remain poor. Imagine all the money people spend on booze or cigs over 30 years, it adds up. The what they spend on health problems from the booze and cigs. They bitch about the rich but squandered away their money for nothing that would help them.
Adverse life experiences such as physical/emotional abuse may make some turn to alcohol and drug abuse (and smoking). These are just coping devices and without them they may suffer with unrelieved stress which can lead to other health problems.
There’s more to it than just a bad habit they picked up.