My guess is a little different...
I think they could have implement such a feature easily, but they probably would not because of the following concerns:
1) No one else is doing it, Anthem does the quick measure thing but while their fans rave about that, in reality it is almost useless the way they implement it, like a joke, a semi useful (deserve some credit for sure) joke..
2) They know full well the post measurements would not look pretty versus the predicted, most likely because the predicted are a) predicted, so the results will naturally look like the target curves as in theory they are supposed to, b) the REW like curves will invariably be for the mmp only, otherwise users may be confused, and it would be hard for them to do practically speaking, to measure all mic positions and in exactly the same locations as the positions used during calibration.
3) Such RC software likely do their own averaging for the predicted results, so it they do the post correction measurements, the results may in fact look like the predicted results they show now, but would not likely look the same as those people obtained with REW, in that case, people may complain just the same.
4) Because of the above reasons, and likely more, such post correction measurements may end up putting them at disadvantage, it would like like for AVR/power amp manufacturers to publish their all channel driven rated output for 20-20,000 Hz at 0.01%THD, when most others do the 2 channel one for 1 kHz, That could be suicidal from marketing standpoint!
Again, that's my guess albeit I believe it is an educated one based on my understanding of how they work. One of these days I will try to use REW to measure all mic positions used in the calibration process, to do that I would have to mark the positions somehow. I believe if I do that, and then do some kind of averaging, the results could match Dirac's predicted ones a little more. It still won't be exact, as Dirac, also Audyssey, will not likely do their averaging like REW does.