All speakers are governed by the laws of physics. There are in particular three parameters that are inter-linked : Box size, low frequency response and efficiency. This limits your choices. You cannot have both a small box and a high efficiency and an extended bass response. If you want low bass and a small box you cannot have high efficiency.
If high efficiency is a goal, then the speaker can play loud with only a modest power amplifier, but will not have good bass response. However, the number of opportunities for playing loud music at home tend to be limited. Most of the time we listen at only modest sound levels. As such, we sacrifice bass response for all our music, for the trade-off that occasionally we can play loud.
The Debut series priority was to be able to have extended bass and so we gave up somewhat on efficiency, recognizing also that higher power amplifiers are lower cost than ever, if one needs the ability to play loud!