Brazil is also considering making USB-C chargers mandatory for iPhones
theverge.com
theverge.com
I don't know Apple's reason for not switching the iPhone, but the rest of the Apple ecosystem is USB-C and whatever deficiencies the USB-C ecosystem has (and it has many) standardising on one technology will make life easier for everyone long term.
My tiny country unfortunately has zero technology clout to force these kind of changes through. I am surprised China and India have not used their weight to enforce standards.