"With some modifications" for space environment is a time and money-intensive activity, at least if you want it to work. You'd need some serious justification for such a camera on a mission that is already highly cost-constrained.
There is always a color camera on a Mars rover anyway, usually with much more than three color filters, so its color vision is better than ours. The filters don't line up exactly with our three, each being much narrower for science reasons. But by combining images from filters you can get a very good approximation to how it would look to us.
Which gets us to how it would look to us. That requires some analysis and adjustment as well, due to the very different direct and scattered light at Mars, both in wavelength distribution and intensity. Even at Earth these differences make whether a digital image "looks like it would to us" a very subjective matter. Do a little reading on white balance and color temperature to see how really tricky it is on Earth to get a picture to look "realistic".
Yes, we could fly commercial cameras if we wanted to. But even if they work, they don't automatically solve the "truecolor" problem you have posed. In fact it would be much more difficult to solve that problem with the data you can get out of a commercial camera, as compared to the data we get from our science cameras.