See, I knew my analytical mind could come to good use one day! ;)

I would also guess, that based on the smaller drivers being easier to control, and new cabinet thinking away from standard square or rectangle boxes, the bass is more accurate and less "false". Because large drivers require bigger cabinets, and they were always rectangular or square boxes as they are easier to make. But the material of "older" speakers was typically lacking, and being a common shape, there would be many acoustic issues: standing waves, resonances, vibrations, etc. These could/would lead to bass being "constructed" when music was played - most of which would not be accurate, but enhanced at certain frequencies. This would give the impression of greater bass, but in fact it could be artificial bass.