No Laser Guide Stars for adaptive optics in giant telescopes?

In order to get diffraction limited imaging on large telescopes using Laser Guide Stars one needs to Ire several such artificial beacons angularly dis placed with respect to the science target. Such displacement scales with th e diameter of the telescope. It is pointed out that when this angle exceeds some given figure it can be more efficient to use directly some off-axis N atural Guide Stars. With realistic assumptions it turns out that next gener ation giant telescopes could benefit from this technique and could not requ ire any Laser Guide Star.