This is not correct.
Nothing is blocked.
My suggestion is that if the hardware vendor want this supported under OSMC, they provide a sample device or implement it themselves. OSMC is available freely at Download - OSMC, so it should not be difficult for them to implement this. You should contact them about this as I don’t even have their device to test. Manually editing /etc/modules and not using a modules.d approach (as a bare minimum) is bad.
You will also find that other Kodi distributions (i.e. LibreELEC) do not implement rpi-config because it does not make sense on an embedded media centre distribution.
I also responded to your other post here: ArgonOne Fan / Power Control - #5 by sam_nazarko