We present a theoretical study of the thermalization process of laser-excited, electron-hole plasmas in quantum wells. In particular, the long-time behavior of the light holes is investigated to determine their effect and the role played by the nonequilibrium phonons on the relaxation dynamics. We find that phonon reabsorption by the light holes can result in a significant heating of this population. The consequent retardation in the cooling is further augmented by the bottleneck effect arising out of energy-threshold limitations for the inter- and intraband phonon-emission processes. It is possible to obtain light-hole temperatures exceeding those of the electrons for some values of the lattice temperature and well width. Our results compare favorably with recent experimental observations.