> There's no technical reasons for those to be USB A, and the USB C ones work great.
There's a good technical reason for keyboards and mice to still be USB A: adapters from USB A socket to USB C plug are allowed by the standard, but adapters from USB C socket to USB A plug are forbidden (because they would, together with a common USB C cable, allow creating the forbidden USB A to USB A cable). This means that USB A keyboards and mice can be used in both USB A ports and (with a simple passive adapter) USB C ports, while USB C keyboards and mice could be used only on USB C ports.
Therefore, until having enough free USB C ports in computers is common enough, using USB A ports (with an optional adapter to USB C on the box) on the keyboard or mouse makes sense. This is similar to how, during the transition from serial and PS/2 mice to USB mice, it was common for them to come with a adapter which allowed them to be used either on a USB port or (with the adapter) on a PS/2 port.
>because they would, together with a common USB C cable, allow creating the forbidden USB A to USB A cable
Not hard to do this regardless. Amazon sells A-to-A cables[0]; and Unicomp keyboards for example have a USB-A port in the back, and connect to PCs with a bundled A-to-A cable. Seems like preventing this is a lost cause.
On keyboard it's easy enough to just put a USB-C port on the keyboard and let users either use an A-C or C-C cable.
For mice, having a hardwired cable probably still makes sense in terms of bulk and strain relief, but I suspect that wireless mice are also far more common.
There's a good technical reason for keyboards and mice to still be USB A: adapters from USB A socket to USB C plug are allowed by the standard, but adapters from USB C socket to USB A plug are forbidden (because they would, together with a common USB C cable, allow creating the forbidden USB A to USB A cable). This means that USB A keyboards and mice can be used in both USB A ports and (with a simple passive adapter) USB C ports, while USB C keyboards and mice could be used only on USB C ports.
Therefore, until having enough free USB C ports in computers is common enough, using USB A ports (with an optional adapter to USB C on the box) on the keyboard or mouse makes sense. This is similar to how, during the transition from serial and PS/2 mice to USB mice, it was common for them to come with a adapter which allowed them to be used either on a USB port or (with the adapter) on a PS/2 port.