You’re thinking of the problem with modern solutions in mind. Y2K originates from punch cards where everything was stored in characters. To save space only the last 2 digits of the year because back then you didn’t need to store the 19 of year 19xx. The technique of storing data stayed the same for a long time despite technology advancing beyond punch cards. The assumption that it’s always 19xx caused the Y2K bug because once it overflows to 00 the system doesn’t know if it’s 1900 or 2000.
You’re thinking of the problem with modern solutions in mind. Y2K originates from punch cards where everything was stored in characters. To save space only the last 2 digits of the year because back then you didn’t need to store the 19 of year 19xx. The technique of storing data stayed the same for a long time despite technology advancing beyond punch cards. The assumption that it’s always 19xx caused the Y2K bug because once it overflows to 00 the system doesn’t know if it’s 1900 or 2000.