From the perspective of drivers Radxa is not the hardware manufacturer. They combine off the shelf hardware according to its documentation to create a product.
Sometimes the original suppliers will have drivers, sometimes they just ship documentation and let it be up to the customers to write it, sometimes someone else contributed upstream support. When you get "drivers" from e.g. Lenovo, they didn't write them - they're just sending what they got along.
Nothing would work if there weren't drivers in general, the issue is that hardware can be configured in multiple ways and it's not all going to have have proper support or be well tested. In Linux land, this stuff sorts itself out as people get their hands on the hardware, pretty similar to how e.g. laptop support comes to be.
Sometimes the original suppliers will have drivers, sometimes they just ship documentation and let it be up to the customers to write it, sometimes someone else contributed upstream support. When you get "drivers" from e.g. Lenovo, they didn't write them - they're just sending what they got along.
Nothing would work if there weren't drivers in general, the issue is that hardware can be configured in multiple ways and it's not all going to have have proper support or be well tested. In Linux land, this stuff sorts itself out as people get their hands on the hardware, pretty similar to how e.g. laptop support comes to be.