Why do holes generally move more slowly than electrons in semiconductors?

In semiconductors, holes generally move more slowly than electrons because they function within the tightly bound valence band, whereas free electrons move within the conduction band.1

While electrons in the conduction band are free to move through the crystal, a hole is a fictitious particle representing an electron vacancy in a covalent bond. The movement of a hole occurs as neighboring electrons fill these vacancies, effectively shifting the location of the deficiency from one site to another. Because this process is constrained by the atomic structure of the valence band, holes exhibit lower mobility than free electrons. For instance, in intrinsic silicon at room temperature, the electron mobility is 1,500 cm²/V·s, while the hole mobility is significantly lower at 500 cm²/V·s.231