A truly full-range loudspeaker is a rare bird. There simply aren't that many speaker models on the market that cover 20Hz to 20kHz.
But here's the thing. Even if they were a common occurrence, few among us would be able to enjoy their low frequency contributions.
The problem of course is our old friend the room.
Rooms and low bass are not good bedmates.
The chances of producing a 20Hz note from where your speakers are placed and hearing it at your listening position are about as good as rolling snake eyes.
Where we place our main speakers for best imaging and tonal balance is not likely to be where it is best for bass reproduction.
Which is why, of course, we often turn to a pair of separate woofer boxes called subwoofers.
We can place the subs where in the room they work to support low frequencies without compromising where our main speakers sound best.
Subwoofers are like loaded dice. They guarantee we win.