There is some truth to the concept, Botch. Proper break-in is just making the materials as flexible as they should be, so any crystals in the coatings and other such things need to be broken and loosened. Modern materials and manufacturing processes, which started way back in the 70s, have made any extensive break-in pointless. Speakers do need to enough break-in to distribute any ferrofluids in the voice coil gaps or to knock off any loose particles which might have lightly clung to a part, but otherwise it is pointless.
When all the fun of tweaking turntables, tube amps, and other such things went away in the 1980s, audiophiles who had a compulsion to do things to enhance the performance of their systems resorted to nonsense to replace the very real things they did with turntables, reel-to-reels, cassette decks, and so on which were all highly subject to mechanical and physical tweaking. So, we got stupid cable claims and expensive cables, over the top power conditioner claims, stupid nonsense like cable-lifters, green Sharpies on CD edges, and so on. So, the idea of "breaking in" a speaker is easy to accept as meaningful since a speaker is a mechanism, like cars and power drills. What I love are the folk who still break in their disc players and cables.
But really, just listen to the speakers and enjoy them. They are not going to change in sound in the first several years and will only change a bit over their useful operational lives before they fail.
If you really want to break something in, buy a new lawn mower.