Why the obsession with the lowest octave

If one can get deeper bass without any tradeoff of other qualities, why not? But, such "free" deep bass is hardly ever achieved. Bigger drivers able to push more air usually means more mass (inertia makes such drivers less nimble), bigger cabinets (hard to control resonance), and most significantly, deep bass response usually means much lower speaker efficiency and the need for higher powered amps. To me, there are very few higher power amps that deliver the kind of performance of low powered tube or solid state amps.

I care less about high volume, extremely deep bass than I do about good behavior where most of the music resides in the lower range. I want realistic tonality to bass. There are a lot of speakers on the market with extremely tight, punchy bass, that lack the ability to deliver the proper tone and harmonic structure of lower range instruments (double bass, kettle drums, contrabassoon).

Of course, having the ability to deliver very deep and powerful bass is a big advantage. I just think that, given the usual constraints of size, power requirement, and BIG dollars, there are tradeoffs involved. There are tradeoffs for ANY aspect of speaker performance. The choices one wants to live with depends on taste, type of music, etc.

For example, unless one is talking about a very well engineered active biamp or triamped system, trying to achieve really deep bass using low-powered tube amplification is extremely impractical (look at some of the as-big-as-a-room bass horns of some Japanese systems). But, if you have heard what a really good SET amp can do, trading off some bass capability might be your preference; it is a matter of taste.

I actually have speakers capable of reasonably deep and powerful bass (it has two 12" drivers per channel), but, my chosen amp really cannot deliver room shaking volume. What this combination offers is doing almost everything else right at a comfortable volume level. It is a big system, with a "big" sound, just not a super loud system. I don't use it for home theater, so I don't need things to shake when it plays.

I have heard many speaker systems with full range bass capability (e.g., Wilson MAXX 3), and certainly they do deliver in that respect, but, I have heard few that, on balance, I would prefer over what I have (and those were also not particularly big in terms of bass performance).