Do you carry aroung a balance beam and weights so you can "weigh" things in grams? No.
Do you carry around a scale or tape so you can measure the length of things in cm? Probably not. Some people, mostly geeks do, but most people don't.
Do you carry around a device to tell you the time of day? A watch? Your cell phone? Almost everyone does. It's fair to say that time is our most important measurement.
How many seconds in a minute? 10? No. 100? No. 60!
How many minutes in an hour? 10? No. 100? No. 60!
How many hours in a day? 10? No. 100? No. 24!
So your vaunted decimal system already fails for the most common measurement we make. Come back and argue your point AFTER time has been decimalized.
BTW, how many Newtons does a mass of one Kg weigh? 10? No, 9.8! Why wasn't the meter set so that standard gravitational acceleration is 10 m/sec² or, better yet, 1 m/sec².
I think that the foot is a far more convenient unit of measure than the meter. Note, we have a unit, the yard, which is 91% of the meter, but, except for football, the yard is not commonly used.