Since GR assumes that gravitational waves travel at speed $c$, we expect we would be able to some day detect an aberration effect similar the that of light. Of course, gravitational waves are so tiny in magnitude, we haven't yet unambiguously detected them, so aberration measurements aren't yet possible. However, planetary orbits appear to behave as if gravitational waves have "infinite" speeds, since they aren't seemingly affected by the finite time between where a planet is currently located and the time lapse from Sun's force.
Can someone explain why planetary orbits behave as if gravitational waves have Newtonian-like "infinite" velocities? I'd appreciate a response that doesn't resort to tensor notation.