Here's why:

* Transverse waves require a medium with shear strength. This means the medium needs to be able to resist deformation in a direction perpendicular to the wave's motion.

* Gases and liquids lack significant shear strength. They are fluids, meaning they flow freely and don't readily resist this kind of deformation.

However, transverse waves can still travel through air or gas in some cases:

* Sound waves are longitudinal waves. They travel through air by compressing and expanding the air molecules, not by displacing them perpendicularly.

* Electromagnetic waves are not mechanical waves. They don't require a medium to travel, and they can propagate through a vacuum like space. Light, a form of electromagnetic radiation, is a transverse wave that travels through air and even space.

In summary: While gases and liquids don't readily support the shear strength needed for typical transverse waves, they can still transmit other types of waves like sound and electromagnetic radiation.