Why Kenmochi Hideki created vocaloid?

For professianal musicanians. Vocaloid is'nt the only software with virtual voice for musicans, but others, such as CANTOR, Cadencii, UTAU, iVOXEL, Voceroid, Voceroid+, CeVIO, and more are the same as VOCALOID (except some of the software only speak).