I fix iPhones. The battery needs to be really, really dead before it'll fix the issue. When a battery is reconnected the internal date is reset back to 0 (Jan 1 1970) until the phone connects to a cellular network/NTP server.
Wouldn't that result in the same outcome though? I find it more likely that the clock is reset to a more "sane" time - like Laforet stated as being "well into the 2000s".