@mijostyn You're kinda half right. A point source output follows the inverse square law: level falls off at the square of the distance: double the distance, -6dB in level. In free space. Listening rooms are not free space. Speakers behave according to their width - a 12" wide speaker is an acoustic half-space from about 1100Hz up. This is the 'baffle effect' designers have to take into account that adds up to 6dB of total output above the baffle step frequency. A perfect line source is a line source above the half wave length of the line array height itself. Below that it is effectively omnidirectional, not a point source, just like any other box speaker.
You may find this interesting reading - from Linkwitz Labs https://www.linkwitzlab.com/frontiers.htm#E
Line arrays are a big thing in live sound because they offer great horizontal coverage with good vertical dispersion control and as importantly in large venues, the sound propagates as a cylindrical waveform and so falls off at the inverse of distance, not the inverse square - 3dB per doubling of distance, not 6.dB. Consider this: the difference between one semi of sound equipment and two semis is just 3db. so halving your requirements makes the logistics and cost much more appealing. FWIW Stanal Sound out of Kearney, NE pioneered the use of 'flying' line-arrays in the mid-1970s for such arena-scale acts as Neil Diamond, John Denver, and Bob Dylan. I worked there during that period and helped design some of the cabinets we used as well as some of the first high-output subwoofers.