Evidence of meteoroid impacts is not necessarily rare on Earth, although it may not be as abundant as one might expect considering their frequent passage into the atmosphere. Here are some reasons why evidence of meteoroid impacts can be scarce or challenging to identify:

1. Vaporization and Disintegration: Many meteoroids, especially those of smaller sizes, experience intense frictional heating and aerodynamic forces as they enter Earth's atmosphere. This causes them to vaporize or disintegrate into tiny fragments before they reach the surface. As a result, they leave behind little or no impact evidence.

2. Erosion and Weathering: Over time, geological processes such as erosion, weathering, and plate tectonics can erase or alter impact craters and other signs of meteoroid impacts. Earth's surface is constantly reshaped by natural processes like wind, water, and tectonic activity, which can wear down or bury impact sites.

3. Oceanic Impacts: A significant portion of Earth's surface is covered by oceans. If meteoroids impact oceanic regions, their evidence can be challenging to detect or access. Submerged impact craters may lie hidden beneath deep waters or have been obscured by sedimentary layers.

4. Remote Impact Locations: Some meteoroid impacts may occur in remote or sparsely populated areas, making it difficult to observe or discover the impact sites. Accessibility challenges can hinder scientific investigation and documentation of these impacts.

5. Difficult Identification: Not all meteoroid impacts produce easily identifiable craters. Some impacts might result in less conspicuous features, such as strewn fields of meteorites, shatter cones, or microscopic evidence. These can be difficult to recognize and may require detailed scientific investigations.

6. Preservation Bias: The geological record is biased towards preserving larger and more recent impact events. Smaller or older impact sites might have been erased or obscured over time, making them harder to find.

7. Atmosphere's Protective Effects: Earth's atmosphere plays a crucial role in protecting the planet from meteoroids. Many smaller meteoroids are completely disintegrated or deflected upon entering the atmosphere, preventing them from reaching the surface and leaving behind evidence.

Despite these challenges, there are numerous examples of well-preserved impact craters and structures found on Earth, such as the Barringer Crater in Arizona and the Chicxulub Crater beneath the Yucatán Peninsula in Mexico. Ongoing research and scientific efforts continue to uncover new impact sites and provide insights into Earth's impact history.