As others have pointed out, the coincidence is temporary. It used to be that the moon's apparent size was significantly larger than the sun's, so you could get

As others have pointed out, the coincidence is temporary. It used to be that the moon's apparent size was significantly larger than the sun's, so you could get a total eclipse but you wouldn't see a full corona ring, when the moon's apparent diameter was twice to three times the sun's. Eventually the moon will look smaller and total eclipses will no longer occur. We live at the right time.