For a radio receiver that digitizes over-the-air RF signals (such as an SDR), my assumption (as a DSP guy; pardon my hardware ignorance!) has been that thermal noise dominates total receiver noise, and quantization noise is a slightly distant second.
One reason for this is I assume you would put an LNA as close to the beginning of the signal chain as possible to reduce the effect of noise sources later in the receiver. Thus, SNR would largely be determined by thermal noise (probably mainly from the antenna). Is this accurate, or does it depend on the bit depth of the ADC?
Second question: Is quantization noise typically captured in the reported receiver noise figure, F, or does F only account for thermal noise?
Obviously the answer always depends on the designer's choices. But it seems likely there would be something typical, or a couple of standard cases (perhaps at different price points; I'm primarily interested in higher end hardware).