The French toyed with it. Then the revolution went from pretty fucking epic to mostly embarrassing. Then they killed the guy pushing for a metric calendar and metric time. They brought epic back by taking over most of continental Europe, but, sadly, metric time did not come with them on the campaign.
Anonymous E joined in and replied with this 11 years ago, 1 day later, 1 day after the original post[^][v]#585,731
It took me years to crystalize into a coherent thought, but I now understand much of the reluctance to reject customary units for metric units is that the the metric units with the prefixes have more syllables than people would like to say. For instance, miles versus kilometres. That's why it is common for people to change kilometres to clicks, and kilograms to key-lows (or even just keys in the cocaine traffic lingo).
In a way, we do have metric time units: the second is a base unit. All other time units would simply be powers-of-ten multiples (hectosecond, kilosecond and so on). There is no basis to divide the day into 10 intervals, because those would not be powers-of-ten multiples of seconds. (A calendar day is 86.4 kiloseconds and a tenth of that is 8.64 kiloseconds.) The only work-around would be to redefine the second in order to have say, a tenth of a day be exactly 1 kilosecond. But that would screw with many other units that are partly based on seconds, such as velocity and power.