I wanted to know why tower control cannot tell aircraft to taxi. I listen to a lot of ATC mostly at PHL since that is my home airport, and I hear Tower giving aircraft taxing instructions. Lately there has been a lot of diversions to PHL from airports like EWR, JFK, LGA, IAD, BWI and RDU. Saturday at 8:24pm EDT a British Airways 777-200ER landed at PHL. The tower controller gave the aircraft taxi instructions and told the crew to remain on tower frequency.