Well, this is one of those interpretations that may not be accurate?
Great speaker designers would disagree
2) Can't one manufacture a tower at 8 ohms and 98dB with several drivers to compete with the best, less sensitive speakers (< 90 dB)? Is this only true with horn loaded speakers, and do horns take them out of the ballgame?
If you want real answers, best to ask some of those speaker builders. Manty think theirs is the best approach, so you will have a divergent answer
3) What makes an inefficient speaker better than an efficient one?
That is only an opinion?
4) Why would anyone want to blow a ton of watts into inefficient speakers at low volumes? Would it be for the purpose of hearing nuances? (that dreaded Stereophile word)
At low volumes? where the noise floor of the room will mask the nuances you seek?
5) Are suspension speakers more accurate than ported? If so, do they really need more power? How much more?
Need expert testimony here too.
6) Will a midrange and tweeter benefit from huge current?
Not anymore than it needs from the input music signal.
7) Is a 7 channel power amp necessary for a surround system, or will a beefy 2 channel amp suffice - assuming one is using a mid to high end receiver?
Not sure I understand this Q. Are you asking about 2 channel music vs 7?