1) Bass Extension
2) Efficiency
3) Small Enclosure
The law is that you can only have two of these three attributes in a loudspeaker. If small loudspeaker would have limited SPL and require massive power too produce any lower frequency. If loudspeaker requires little power it has to be massive too produce lower frequency. Small loudspeakers also suffer from thermal compression. As you feed more power into VC it heats reducing efficiency thus requiring more power to produce same SPL. This can cause listening fatigue and premature VC failure. Many assume small monitors on stands are full of audiophile benefits but in reality a small monitor will not achieve its benefits unless in near-field for most systems it would be better to use the SQFT for a floor-stander.