We hope that as we gain experience that this experience will lead to expertise and will help us avoid mistakes. As engineers it would be a sad world if we learned nothing from year to year. As craftspeople we can hope to advance in our craft.
With this in mind, it is odd that in Silicon Valley experience is discounted and discriminated against.
Sure age does not always lead to wisdom, but youth does not always lead to vigor either.
Gary Wisniewski made a great point. Perhaps part of the problem is that those of who have more experience have not properly expressed how this experience can be useful. He wrote that we must express the advantages our experience brings in terms that people who are, for example, running start-ups, can understand.
There is one other factor here which has, so far, been unspoken. Generational conflict appears inevitable in human society. Young people always want to make their mark, to show that like the older generation they are capable of great accomplishment. This means that they will naturally turn away from what the older generation has to offer. In its most brutal form, with generational conflict, the young seek to push the old aside and the old fight this tooth and nail until they can no longer fight.
Outside of the bubble of Silicon Valley and software engineering, experience has been listened to more. As Gary notes, those with experience need to articulate what they can bring to the table. For those who want a better chance of avoiding the pitfalls of the past, opening their minds to what experience can offer would help. Those who do not learn from history are doomed to repeat it.