A society should support and improve people's lives. Capitalism focuses on something else: supply and demand and profit. The problem is that profit or demand for something does not mean that it is a positive contribution.
Drugs are the easiest example. They are in demand but most people feel that at least some drugs make a negative contribution. They're not the only example however. There's also unhealthy food, television, video games and more.
The main counter-argument is personal responsibility and in particular the idea that if someone makes bad choices, that is their fault. However, things are not that simple. From one point of view people make decisions from their own free will, but from another point of view people may be influenced in various ways. For example, consider the amount of money being spent on advertising. That money is spent because it is often a worthwhile investment; it changes people's behaviour. For another example consider food. It's possible to carefully optimize food to increase its appeal to people, but that doesn't have to make food healthier.
America obviously isn't the only capitalist country, but it seems to be the one that's most involved in this destructive cycle of recklessly increasing demand to produce profit. For example you can see what happens when unhealthy food is optimized for appeal, and when advances in video games make them so appealing and available that children spend more time playing video games and less time playing outside. You can also compare BBC to American television and food in other countries with US food.
When the government tries to fix the problem via laws, that can fail and just cause more pain and suffering. The problem is that laws are used as a crude tool which essentially amounts to ongoing terrorist attack. They say that if you do something bad, agents of the government can take your money, possessions and freedom. For example the US war on drugs hasn't worked out very well, and America has the highest incarceration rate in the world. Laws don't seem to be able to create a substitute for a healthy culture. For example, compare what US alcohol laws do with other countries which have a healthier culture surrounding alcohol.
The worst part may be how American culture is spreading throughout the world. Look at its icons: companies like Coca-Cola and McDonald's. That can't be good. The problem is that the main motivation to spread comes from companies who want more customers so they can increase demand and profit.
Culture has a sort of inertia, which is a double-edged sword. It means that old healthy patterns can persist, but it also means that when new unhealthy patterns form, they tend to persist. Because of inertia, culture has value. Positive patterns are an asset and negative patterns are a liability. People need to keep this in mind.
The main hopeful thing I see is that the same things which cause problems can also be used in a positive way. For example, maybe capitalism would work if sales involved the true value of objects: both their current value and their long-term value and/or cost. Also, an ability to effectively influence people can also be used to influence people to make healthier choices. Many things cause harm when overused or otherwise abused, but they still can have a constructive place in life if used intelligently.
The main obstacle I see is lack of awareness about the fundamental problem. Awareness seems focused on particular instances of the problem such as the mortgage crisis, obesity epidemic or messed up health system. People need to understand the underlying pattern which needs to be fixed.