Writing destroys the ability to memorize

Human brain is a wonderful organ composed by millions of linked brain cells. Information from the outside arrives to our brain through our senses and just a small part of this data is saved in our brain. However in the actuality we are missing the ability to memorize, because most of the times we have to write in our agenda or in our cellphone to remember things we have to do next.
I am completely sure that those people who can’t remember a simple name or a short telephone number need to write it down on a paper and they became dependent on writing. I am not saying that it is not useful nowadays; I recognize that writing is necessary tool to remember things, and many of us are depending to write so much to remember, the problem here is that in a not very distant future probably we lose completely the skill of remembering things. For that reason we must not be careless or wait until it is too much late to exercise our memory, for example the reading improves the concentration and the memory.
I expect people to reflect about that and don’t depend on writing to remind everything.