Prescriptive grammar is as presumptuous, as naive, as futile as prescriptive meteorology. Language and the process of language change are natural phenomena. They go on, indifferent to all of our wishes and musings about what should and should not be. Language is an amazingly complex thing because it is for the most part the very embodiment of how the human mind works. I believe that what defines humans is their ability to manipulate thoughts, meanings, the boundaries of reference of things concrete and abstract.
Language is the tool.
This is what gives language its power and what gives humans the ability to create. Language is not set in stone. Every utterance of every word is a metaphorical use, not exactly like any use ever made of it before. That is why it is also the very nature of language to change. It is, as are traditions, dress, shared history, collective memory, and much more, part of Culture.