Re: Perhaps developers should work offline
"Requirements change,features added = new product."
Based on the assumption that a full product is bigger than an update - and bigger than the original as it contains new features, then this presents the customer with at least the same risks and possibly more than updates.
"My code has never been exploited and has never needed any updates, this simply because it was bespoke i.e. different for each customer."
Been there, done that. But neither you nor I have had the problems inherent in supplying product to a mass market. I don't think we'd have been in business very long if we insisted on selling new products for every new feature, at least, not without the Stockholm syndrome of Windows users.