Individual components won't guarantee proper dynamics in a system. In order to preserve the dynamics in a recording it is essential to have a system with suitable gain structure between components. If you can't turn your volume control past the 9 o'clock position without your system getting too loud, then your gain structure is off. Similar mismatches can occur between the preamp/amp or amp/speaker. It's not as if there are perfect interfaces between components, but there are wrong ones and those will degrade your system's dynamic performance.
Regarding loudspeaker, I don't think that higher efficiency is what makes some speakers sound more dynamic, instead I think it's related to larger driver area and the amount of air that is excited. It's my observation that loudspeakers with twin 15" drivers have greater dynamic capabilities than a loudspeaker with a single 6" cone. The reasons why are obvious and if you wanted to reduce it to a simple statement -- small speakers won't sound as dynamic as larger speakers, assuming appropriate caveats.
Regarding loudspeaker, I don't think that higher efficiency is what makes some speakers sound more dynamic, instead I think it's related to larger driver area and the amount of air that is excited. It's my observation that loudspeakers with twin 15" drivers have greater dynamic capabilities than a loudspeaker with a single 6" cone. The reasons why are obvious and if you wanted to reduce it to a simple statement -- small speakers won't sound as dynamic as larger speakers, assuming appropriate caveats.