I honestly don't get it when people have to do all that stuff to "protect" themselves instead of just... not going on Facebook 15 times a day? I consider myself like an easy target for addictive services but, I don't know, I guess I just have better things to do.
For instance, I noticed myself picking up my phone and browsing certain websites (dopamine sources) whenever my thoughts wandered into a topic I find distressing -- instead of confronting those thoughts and thinking them through. For me, Facebook happens not to be addictive, but other sites are (for instance, Quora). I was wasting hours on those sites instead of doing productive things.
Setting up a content blocker to make me think twice before visiting them has helped. So has adding an app that I can set to block using my phone for a given period of time, forcing me to put it down and do other things.
Addiction is built-in in these apps from every possible way. There are lots of information on how they do that. Your comment is like saying, why don't people just stop taking narcotics, there are better things to do.
I've given serious consideration to limiting myself to mobile versions of the game I'm addicted to, but I can't answer 'yes' yet!
I can also vouch for the effectiveness of this strategy based on slow motion Street Fighter 4 on a machine with an integrated graphics card.