The tuning required to run a proper rear stage is quite large, most people would not have the possibility of tuning it properly. And even so, what would you really gain from running a rear stage? If anything the depth would be worse.
I am a novice when it comes to sound quality, I have only been competing for two years. Though I have learnt a fair bit in the two years competing, and the years before that with car stereo.
I have yet to see a car do well with a rear stage in MEA sanctioned SQ Competitions, nor have I seen any of the current Australian number 1 competitors use a rear stage
I disagree with most surround sound in cars, even the like of Bose/Dolby as you mentioned, they are often poorly setup in my opinion, I've listened to $7000 optioned Bose stereo's in brand new Alfa Romeos only to have it sound poor.
For people here, with a limited budget, in a 2 door coupe, rear speakers would be a waste of money and and would only on occasion benefit the passengers.
If the whole speaker budget was spent on the fronts only and a decent amp to run them, the person driving would be much happier.