Advice is easy, execution – hard
You already know how to solve your problems, so why haven't you done it yet? If you're anything like my friends, you can probably give me a long list of actually good reasons, and also of things you've tried that didn't work. And yet, judging by the amount of self-help and advice books floating out there, you'd think any problem was solvable. What's going on?
Natural selection.
Advice propagates best if it sells the most books or newspapers, if it sticks in people's minds and gets repeated a lot. The more plausible it is, the harder to refute, the more it propagates. Unfortunately, "obvious" does not correlate with "actionable" or "easy to implement". Often, it comes down to "eliminate the symptoms of the problem".
Here's one common example: cutting out caffeine, sugar, smoking, and alcohol. These are all common ways of mitigating the impact of stress or other health conditions (anecdotally, coffee has an antidepressant effect). People adopt them when they have no other ways to e.g. rev themselves up for a job that requires more energy than they have. The real solution is to change the jobs (or professions). But that's not actually easy, is it? It takes time and money. Some people don't have enough energy for any job, but they are also not financially independent, so they're stuck.
Thing is, explaining this web of interdependent constraints is usually long-winded and boring. At least some of the nodes in the web are going to be systemic issues, which people usually shy away from examining. It's much easier to narrow down the scope of conversation, and castigate the person for their "lack of willpower", because "they could just stop if they wanted to".
Thus, easy advice sells and propagates, even though it's not actually very useful or applicable to most people.