While the Birkin is THE iconic bag in the fashion world, it's hard to find a perfect parallel in the watch world.
Right now I see Birkin as a combination of Rolex and Patek. Some similarity I'll outline below:
Rolex: symbol of wealth, well known, everybody wants one - and every celebrity have one, iconic, high resale value, massive secondary market, cult status (remember Jane Birkin is a cult icon).
Patek: prestige, status symbol, consumers are played to the manufacturer's hand - we BEG to take it off their hands, not the other way round, able to charge any price yet there is still a waiting list.
Whether the Birkin will stand the test of time I'm not so sure. However, apart from being an "IT" bag, the Birkin also represents the highest quality a handbag can get, which I believe is something that, at the moment, have no viable substitutes. None of the other fashion houses manage to produce a bag of this standard - yet.
As for the watches that will become the Birkins of 21st century..... Looking forward to see your other installments first