So, I see myself as a fairly normal person. I have a laptop that has all USB-C ports (macbook pro of course.) And I use various arduinos, many of which have the small microUSB plug. MicroUSB is also used by about a zillion android phones... it's not rare.
So, it seems that it would be quite common that people would want a cable that has USB-C to microUSB? People don't want to use dongles forever, right?
Large IT malls had none. Even online sites, you wade through hundreds of cables that have USB-C to one other other weirdo flavors of microUSB.
ANYWAY I finally got mine on a chinese eCommerce site. (Amazon is out of reach in my country.)