Bombaywalla, I would add just one point to your IMO excellent list of reasons for the proliferation of speakers having problematical impedance curves. And that is that there seems to be a tendency among many audiophiles to equate the ability of a speaker or other component to resolve hardware differences with its ability to resolve musical information. Thus, if on the basis of reviews, user comments, etc., a speaker acquires the reputation of making amplifier selection particularly critical, it will in the minds of many audiophiles create an expectation that it will resolve musical information and detail better than a speaker for which amplifier selection is less critical. While of course, as this thread makes clear, that is by no means necessarily the case.well-said Al!
best regards.