A patent is meant to encourage people and companies to share the details of their inventions, instead of keeping them secret. In return the inventors get protection for a certain number of years.
we're getting patents intern could re-invent from scratch in a week in whiteroom
That was the stated purpose of a patent.
The modern purposes of patents seem to have shifted a long way from that.
I wonder how much of ADSL's advantage is due to trade secrets (spread across many vendors) versus how much has been published as patents.