Whatever the success rate is of achieving goals... that's really just one of the many "LoA" side effects, not LoA itself. Duh. And it largely depends on how people go about it anyway, and we all know how good people are at understanding "LoA"... just look at your own article HAHAHAHAHAHAH (it's pretty damn funny to be honest). Most are looking for shortcuts when they set goals. That's still "LoA" btw... when they don't achieve those goals.
Time is a factor that all manifestations of thought and feeling operate with in the physical plane of reality. When your vibrations are consistently high, your desires manifest faster. The more enthused, excited, and emotionally charged you are about something and the better it feels, the faster you ll see it show up in our life. Higher vibrations are closer to divine life and they will attract all good things you divinely desire in your inner being. All things are spirit in form.
Having the necessary mindset for the creation of your vision means that your mind – both conscious and unconscious – must FULLY ACCEPT the new vision. In other words, you must believe that what you desire can be achieved and is possible. The reason this is so important is because if you have any opposing thoughts or competing commitments or beliefs that contradict whatever it is you’re wanting to manifest or create you will not obtain the desired results.

How Do We Manifest

You claim that "positive thoughts always resulting in positive things" is not the basis of the LOA. In part you are correct. The foundational basis in science, as I alluded to in the article was that thought stuff particles travel through ether (not air) and interact with formless stuff to create whatever it is that you are thinking about. This was how "the law" started.

How To Manifest What I Desire