First of all, I don't know if a a totally flat response curve from your speakers is ideal, but a lot of people seem to think so and it seems like it should be easy to achieve.
The outlaw 990 already has a mic and auto calibration software, so it seems like it would be easy to incorporate a graphic equalizer in the OSD (why have equalizers gone out of fashion lately, anyway). The equalizer could be arbitrarily accurate, say, to intervals of 1/12th of an octave. The mic could record a frequency response tone and measure the speakers response, then invert the frequency response line and add that bias to all outputs from the pre amp / processor. This would be easy to do and would work, so why isn't it done?

Although in some circumstances EQ can be a big help, let me be a devil’s advocate:

1. Over a ten octave range, a 1/12th octave EQ would have 120 adjustment points per channel, or 840 total for seven channels, and that’s just for level without allowing for bandwidth, center point or other adjustments.

2. Especially in smaller listening environments, you would somehow need to have different EQ settings for each listening position. I’m one of those people that believes if a physical acoustic problem exists in the loudspeakers or in an environment, deal with that problem as much as is reasonably possible first, then modify the signal as a minimally as possible.

3. In order to have a reasonable number of parameters to handle, many EQ’s are parametric in that they allow, for example, twelve adjustment points and have some analysis that takes place in order to determine which twelve areas in the sampled spectrum need the greatest amount of correction. This tends to overcome some problems, possibly introducing others, but doesn’t really give an ideal “flat response.”

4. What about added cost that some don’t want to pay for in every unit? Is the EQ capability in Receiver X going to meet marketing or sales promotion requirements and yet fall short in a “sound system engineering” sense?

There are more reasons, and this can open the door on a huge subject, but I’m going to limit my time writing.