So I wonder if our best way of avoiding addiction is to do whatever necessary to cultivate a lifestyle that supports being in a state with less anxiety, stress and sadness.
I believe in this very, very much; and I really appreciate your observation on sadness. Nevertheless, your last observation is indeed a valid one (I cannot be a healthy person working a standard 40-hour week). I suppose this is left for us to actually make the effort to invest in our mental well-being. You know, with the hours we have left, instead of sitting in front of the TV for 2 hours, or the computer for that matter; what about timing it 30 minutes and the other 1, 5 engage in some relaxation, reading etc..
I do feel we live in times where in order to enjoy emotional well-being we must be proactive about it; and because of the chronic stress we live under the temptations overpower us to the point they become addictions. The way I see it is that it will always be a battle - that is why you feel you have tried repeatedly. For me, the key thing here is not to stop trying. It will not always work, however, as long as it work most of the time, you will be contributing to your mental-health.
All the best to you :)