Yes and no. Your point about bitrate being important is correct, but you're still largely wrong.

The actual main thing about RAW is that the transforms for white balance, gamma, brightness, colour space, etc. haven't yet been applied and baked into the file. With JPEG, at least some of those transforms have already been applied, which then limits how mucn you can do as opposed to starting with the untransformed sensor data.

You could definitely do much more with a 12-bit JPEG than you could with an 8-bit JPEG, but still not as much as you can do starting from RAW data.

the absolute main thing is debayering, and yeah, then colorspace transformations etc