Over copper it's easier to provide asymetric connections because the provider can better manage interference between different cables. When there's no interfere

Over copper it's easier to provide asymetric connections because the provider can better manage interference between different cables. When there's no interference problem it's only a question of allocating the bandwidth. Ideally the connection would auto-adjust and provide up to the full bandwidth in both directions instead of constant half/half or 0.9/0.1.