> I have yet to see your definition of what constitutes a color space
"Color Space: A three-dimensional space or model into which the three attributes of a color can be represented, plotted, or recorded. These attributes are usually called hue, value, and chroma." "More commonly, color spaces are built on external references, such as the CIE system of measurement. "
Technically, a camera sensor is sensitive to some range of frequencies, which includes infra-red (and probably x-rays). The filters block certain frequencies and there are a set of grayscale numbers output which represent the data as seen through the red, green, and blue filters. Those data are linear (counting photons), which isn't useful until they are mapped into a well-defined color space, wherein the relationships among similar colors are handled consistently. It is then useful to convert from one color space to another, because every printer, monitor, etc. has a restricted range of what colors, saturation, and intensities/luminosity can be displayed. When you try to map a wide colorspace into a narrow one, then "out of gamut" colors are undefined. Convert your favorite photo to the smallest colorspace: one pencil and paper. Artists do it, but they make a lot of decisions about what gets left white (paper) and what gets a gray or black pencil. Even smaller: Adobe Photoshop "threshold" maps to black or white, no grays. The only decision is the cut-off point.
The camera color space is NOT well-defined without knowing the spectral response curves, etc. In these discussions. most people refer to well-defined color spaces: sRGB, Adobe RGB, LAB, ProPhoto .