Hehe yeah, my first proper 1080p dashcam was the Lukas LK-7500, it had a whopping bitrate of 11.
Dont get me wrong i would like to see higher bitrates all over the board, but not really as long as measly little memory cards are the storage media.
Also as mentioned, it is not only a matter of what the memory card can handle, before that in the chain there is the SOC which also have its own set of limitations.
The new high end novatek SOCs will easy do 1440p/60 at 40 mbit i am sure, probably even more than that.
Also the dashcams are not really cinematic recorders, i have tried my osmo action out in the windscreen running 4K/60 and 100 mbit, but that did not mean it was catching more plates ( the only detail i care about in a dashcam )
But of course there was much less Lego like in the footage and also more detail in roadside grass ASO i wizzed by at 80 km/h, but t his was also a nice sunny day, though i had put on a ND32 filter.
Of course thats youtube, so never nice footage just show the cirsumstances under which i performed my recording, the raw footage on my computer of course looked much better, and very much better than any of my dashcams.