A choice more than an omission really - which speaker would you aim the remote at? What if they're too far apart so the remote can only operate one speaker at a time? Would you have one remote for each independent speaker or add additional cabling with an umbilical cord between the two to ensure synchronised control? How long should that cable be? How would it work as a 5.1 system? Would you add a digital display on the front so you could see a volume readout? Would you avoid some of these issues by using a Bluetooth remote and the complexity/cost that adds to the design? Maybe use app control and manage every device format that has to work on and their own library access/update/store requirements leading to potentially frustrating reliability issues?Oh, what a silly omission on their part, really!
In the end, after MUCH debate about remotes, connectivity, wireless etc. we decided to keep the speaker as simple and pure as possible, concentrate on sound quality/reliability and leave volume control down to the source which can be chosen for functionality to the user's needs.