Colour sensors have 1/4 the resolution of a B&W sensor with the same number of elements (1R, 2G, 1B sub-pixel per pixel). If you know you are going somewhere that is uniformly grey you get more data from the higher pixel count. Also, an RGB sensor doesn't actually tell you anything about the colour of an object, it just looks like the colour of the object to a human eye. To know the actual colour of something you need to use a spectrometer to measure how much of each wavelength of light is being reflected.
tl;dr RGB colour cameras are pretty but don't help with science
I know there are other factors it just feels like the only people getting screwed are the little guys. In Canada the rates that third party ISPs pay and charge are dictated by the giant telcos. Our regulating body even allowed the telcos to raise prices to the point where reselling is no longer viable. Fucking the little guys again.