You're focusing on the extreme unrealistic end of what people were worried about with Y2K, but the realistic range of concerns got really high up there too. There were realistic concerns about national power grids going offline and not being easily fixable, for example.
The huge amount of work and worry that went into Y2K was entirely justified, and trying to blow it off as "people were worried about nuclear armageddon, weren't they silly" is misrepresenting the seriousness of the situation.