Y2k was not a hoax. Myriad computer systems used two-digit years, and could not cope properly with date calculations involving year 2000 dates.
Just because there were no problems with major, visible impact to the public doesn’t mean there were no problems.
The Y2K hoax was not that computers weren’t using 2 digit years, it was the hype and panic over the coming armegeddon. Its similar to global warming in that the hoax is not that the planet warmed a little over the last 20 years, its the hype and panic over the coming armegeddon.