The reason is because while you want to use the low end the general public does not understand that USB-C is the connector only and that various levels of power and data depend on the cable and the device at both ends.

If you sell a 10 port USB-C charged someone is going to plug 10 MacBooks into it and complain it doesnt work.

The best I have seen for what you want is

https://ca.ugreen.com/products/ugreen-500w-desktop-charger

but is not cheap at all or something like

https://www.amazon.ca/Powered-Aluminum-Adapter-Computer-Prin...