Its because pro/PA demands larger drivers with more power handling and output. If you look around however you can find more pro speakers which are small. P.Audio, 18-Sound, and Celestion also make 6" drivers and celestion make a 5" model as well. Radian have a high efficiency coaxial 6.5" too. Theres nothing stopping you from using the LA Eminence drivers in a non-line array application if they will suit what you want to do with them.