It's a chicken and egg scenario. Motherboard manufacturers load up their I/O panels with USB A ports because people demand them. People demand them because all their perhipherals, like the dongle for their wireless mouse, are USB-A.

Logitech recently released an updated version of my mouse, the G Pro Superlight 2, and the damn thing still ships with a USB-A dongle.

With how many ports modern motherboards often ship with, I would think they could at least split the difference and give me 1/2 USB-C and 1/2 USB-A. but nope, my 2 year old motherboard only has 1 USB-C port on the back and a dozen USB-A. Then at least we would have a path forward.