When up to date becomes out of date

How long does it take for contemporary social satire to become social history?
Recently I have been embroiled in the fiddly task of turning my first seven novels into ebook editions.  They were published originally in hardback and paperback in US and UK between 1969 and 1988.  Conversion of work which was written on typewriters, pre-computers, involves scanning of the printed pages, then a process called OCR (Optimal Character Recognition).  The result is a Word doc but one with a lot of less than optimal character recognition.  Each line has to be checked for errors.
I dislike reading what I've written in the past.  It can be squirm-inducing.  But these early novels were written so long ago that they (almost) seem to be written by someone else.  I'm actually fascinated by the way they have become period pieces.  A London house cost £10,000.  One heroine used a threepenny bit to hold up a stocking.  Single parents were a rare species.  The writer of those Swinging Sixties, Serious Seventies novels took a cool, slanted look at what was happening around her and served it up as entertainment.  Many of the issues that puzzled her casts of characters have remained the same.  As the French say, the more it changes, the more it stays the same.   Only the context dates.   When will cell phones become antiques?
By the way, WritersReadersDirect.com is back in business.  Submissions welcome.