A little bit of support goes a long way. Direct actions do guarantee results, it's not wrong, but there's more to it than getting it done and saying it's done. I'll use addicts as an example because it's something I know. A family throwing an addict away in jail is a direct action. It will force them to sober up, it will have them off the street as a potential criminal, and as a burden to a family not willing to take the extra time and effort to help their child.
It's a guaranteed result, but how long does it stay effective? They come out of jail, sober, but not with any more knowledge than they had before jail. They don't know how to deal with their addiction, or how to stay sober, and most end up doing the junk again.
Now, I'm not saying direct actions do nothing, I think that there NEED to be some things done directly and soon. However, I believe (and I may not be right) that every direct action needs backing, things to keep it staying effective.
For example, with the addict, your direct action would be to put your son/daughter in rehab. Rehab is designed to work with addicts, with programs to support a healthy drug-free lifestyle, and help addicts find what makes them addicted to drugs so they can fix the problems. It's going to achieve results, but after rehab, there's still more to do. You have to support them, be there for them, find out why they go to drugs, etc.
There's no correct method. It won't always be a direct action + support = result. Sometimes it's backwards, again with addicts: some aren't ready for help, and you support them (not their addiction, there's a difference) as much as you can until they are ready, which means it would be support + direct action = result.
What I'm trying to say (or what I think I'm saying, I got carried away) is you need BOTH. One way or the other is probably not going to work.
Also remember that result does not equal solved. Result is a change. A lot of addicts slip up on their way to sobriety. You just keep working to get it better and better.
(sorry if it doesn't make sense. Also, sorry I made it sound like the thread is about addicts. It's not, just an example I used to explain something. I didn't know any other way to say it.)