... adding power and dynamic headroom to less sensitive speakers can balance things out
Depending on the particular speakers you don't just "free-meal" add dynamic headroom with more power when sensitivity sits in the low end. Lack of sensitivity is the main culprit here, and more power will only get you so far until thermal compression/"modulation" sets in and becomes a negative factor. Usually inefficient speakers don't compensensate with more power handling - rather to the contrary compared to pro segment, and much more efficient drivers - and so the issue is really made all the more worse.
In any case having prodigious power and/or otherwise efficient use of it, like with active configuration, is a good thing, and will certainly maximize the potential of a given speaker system macro dynamically - not least with high quality, higher power handling drivers - compared to a more anemic, inefficient power delivery when passive filters are involved.
... and considering high sensitivity speakers often sacrifice low bass to get those high numbers sometimes it's worth the investment in source instead of integrating a subwoofer.
Unlike low sensitivity and the inherent, practical limitations with headroom here, high sensitivity and low end extension aren't mutually exclusive but rather a matter of proper sizing (so, in this case you actually have your cake and eat it too). That is, high sensitivity capable speakers are typically attenuated quite a lot of dB's with resistors in a passive, horn-loaded mids and tweeter section to meet their lesser sensitive and direct radiating woofer counterpart, and this is not without implications, both with regard to overall coherency and getting the most out of the horn-loaded sections (another reason to go active here and/or all-in with size).
When the system sensitivity in the rarer cases approaches or even, very rarely, slightly exceeds 100dB's with horn-loading it usually means a some 35Hz cut-off at the lowest with stand-alone main speakers. Listening to the bass of such a system however, like the Khorns, is certainly - by a wide margin - the preferred sonic scenario to my ears, also when factoring in a by-specs relatively limited low end extension; honest 35Hz gets you a long way in most cases, and reproduced via more unadulterated, higher sensitivity bass sections will come off feeling even deeper and more convincing. As it stands though few a willing to let size have its say..
