You're overthinking the whole ONVIF thing. If you have a look at the list of cameras in Blue Iris I think you'l find hundreds, at least, that are not specifically ONVIF compliant. Many that are ONVIF compliant don't allow configuration of critical settings, like bit rate, constant or variable bit rate, iframe intervals, control of IR onboard IR lighting, and a whole pile of other little, and not so little, things that you probably want to tinker with. Generally speaking, as long as a camera has an RSTP stream Blue Iris will recognize it and chose the best configuration for that camera on its' own.
Bulk price can be cheaper , in the future we will bring down the price on amazon , right now shipping cost still bit high. Will try to make purchasing as simple as we can!