The easiest answer is they are fixated on their own lives and their own health. 

People think of themselves and their own situation 99% of the time.

This is why people never hear you when you tell them what is wrong. This is why people will check out in the middle of the conversation because you are not appealing to their sensibilities. This is why they will always tell you what worked for them because they can't handle the cognitive dissonance in their own life.

So, the next time you hear this, you will know they are trying to fix themselves, not you.