Programming isn't as simple as find save replacing something like that. What if the date variable was only created to hold two digits? What if you're comparing data from two sources that use different data standards so now you have to write something to consider for that. I was still a kid in 2000, but I'm a career programmer now and have worked for financial software companies. These are software with millions of lines of code, and very very rarely is updating something like that as simple as find and replace copy paste. It literally took years to rewrite things for Y2K and keep systems in sync at the time across all sorts of industries.