Whatever its proper definition is, the above-named theory is based on the idea that markets are big pools of water in which human beings are fishing for stuff and other human beinhs and companies are dumping stuff in the water for them to fish. In a lot of cases, human beings are both dumping stuff and fishing for stuff at the same time. The tools they use to fish in this water are money, the amount of which - like a fishing line or net - determines what kind of fish, their size, numbers, variety and edibility you will get.
Further, they describe "efficient" market forces as this pool being in a continuous a natural or organic state of change and balance where people ask for things they want or need depending on their balance and other people and/or businesses doing their best to supply these needs. If people want a sandwich to eat in the morning, or a sun hat to keep the sun's hot rays from their foreheads at noon or a tent to sleep in at night, the suppliers produce, distribute and get paid. If the people fishing do not want, producers do not get paid and do not produce in no particular order.
What has happened instead is, increasingly, businesses have realised that while people/customers are increasing and thus the pool is growing bigger, their needs and/or wants do not grow in proportion, tandem or infinitely, so what they do instead is destroy the stuff people have already fished through methods that include but are not limited to destroying their usefulness, dumping stuff in the water that meets their own specifications and forcing it onto the fishers' hooks and nets.
That is what is happening, and it will backfire at some point once people realise they do not want a part in it.