The only reason base 10 looks logical and familiar is that we grew up with it, so it's now an entrenched in the way we see numbers. Around the world there are and have been all kinds of cultures with all kinds of counting systems like base 5, 20 and 12. Everybody is comfortable with the system they grew up with.

We could have a variation of what percentages are in base 10 in base 12 too, but they will be per 144 instead of per 100. And there would still be round figures - 10% would be 1/12 instead of 1/12, 1% would be 1/144, 30% would be 1/4, 40% would be 1/3 and 60% would be 1/2. If you want a basic intuition for percentages in base 12, imagine a clock face and add zeros and the percentages correspond to the distance around the clock covered from twelve - 3 is at 1/4, 4 is at 1/3 and 6 is at 1/2.

The base 10 percentages are both equally arbitrary and equally logical, we have just gotten used to them.

And yes, for adults, it might actually be impossible to develop a base 12 intuition that is as good as our already developed intuition for base 10 is and base 10 would probably always feel more natural for most of us. That's yet another reason we'll most probably never see base 12 implemented in any way.