Previous connectors had inherent flaws. The USB-C connector is sturdy, is easy to use etc. But even if we had made the micro-usb connector the only legal connector, it wouldn’t have been the end of the world. Existing standards can be improved instead of making new shapes each time.

A and B are the original, used for host and device sides, respectively. C is the same on both ends of the cable because figures there's device classes which can sensibly act as both, in particular phones. It's also the most modern of the bunch supporting higher data transfer and power delivery rates because back in the days where A and B where designed people were thinking about connecting mice and keyboards, not 8k monitors or kWhs worth of lithium batteries.

The whole mini/micro shennanigans are alternative B types and quite deeply flawed, mechanically speaking.