Maing cited: "However the main obstacle of the silicon photonics is the nature
of the silicon, which is a semiconductor with an indirect band gap, making lasing in the
silicon material practically impossible."

With emphasis on "practically". Of course silicon can lase somewhat, because otherwise a thing like Silicon Photonics would not exist at all. However, since silicon has an indirect band gap while gallium arsenide has a direct bandgap, emitting and detecting light using Si is very inefficient compared to GaAs.