I can't understand what you are talking about, my post didn't have an argument, never mentioned frame rates or bit rates, and never made any point about dual/single cameras
I have all my dashcams set to 30fps, no advantage to a faster framerate for a dashcam ... unless I'm on a racetrack! As for bitrate, the B1W single dashcam has the lowest bitrate and the A129 dual dashcam has the highest, except for the F1, which isn't really a dashcam. I don't see any connection between single/dual and bitrate.
My lowest quality dashcam is a single camera, the best a dual camera!
I have a 4 output USB charger installed in my interior light, neater to plug in two single cameras with a cable each than the dual cam which has 2 wires connected to the camera.
My Gitup F1 writes nearly 80Mbps to the memory card, my B1W dashcam writes 12Mbps, therefore the memory card in my F1 is capable of supporting at least 6 video streams of B1W quality, and the B1W is quite a good dashcam, it comes top of the
Best Dash Cams of 2019 page. I don't have a six channel camera to prove it works but I don't see any problem.