I think for practical benefits, it is better to have 3, 4, and 8 channel amps and forget about the 7 channel version, given that there are no shortages of 2 and 5 channel amps by default.
People can then buy:
5.1 - One single amp.
7.1 - One single amp, biamp the center if the owner wants to give it a little more juice.
9.1 - Two amps, 8 channel amp + a mono block, or two 4 channel amps.
11.1 - Two amps.
13.1 - Two amps.
The 7 channel version has very limited applications/flexibility as it does not really "add up" all that well.
For the 7 channel version to be more viable, it needs to be modular, with up to 2 slots for 2 more amps, any more than that will be killed off by
@TLS Guy preemptively..