Size is the distraction. A lake can hold an entire mountain range in reflection because the image depends not on the mountains' bulk, but on how consistently the water redirects their light toward an observer. Stillness supplies the order. Under specular reflection, a smooth surface preserves the directional relationships between incoming rays, allowing separate peaks and ridges to remain recognizable.
Height takes undue blame. What disrupts the picture is chiefly the slope of each ripple, which changes the surface normal, the imaginary line perpendicular to the water at that point. Small tilts redirect light. When a reflecting patch tilts by one degree within the plane of incidence, the reflected ray turns by two degrees, enough to shift which part of the mountain or sky reaches the eye. The image breaks apart. Adjacent patches now send light from different directions, so a ridge can stretch, split, or vanish into moving fragments.
Reflection survives the damage. A ripple only millimeters high can have steep sides if its crests sit close together, whereas a broader swell of greater height may tilt the surface less. Spacing changes the outcome. The eye receives a shifting arrangement of reflected rays, and an exposure that spans their motion can blur those fragments further, even though the water continues reflecting light. The mountain remains untouched. Beneath its steady outline, the lake offers not a smaller mountain but a thousand incompatible views of the same one.