Why all these videos of distant, flying things?

The majority of UAP/UFO sightings are of things floating or flying through the sky, and they rarely if ever leave anything behind for us to study.

Our visible interaction with the world seems to be far more varied than UAPs. Like UAPs, we fly through the air, but we interact with the ground and other entities. We also have artifacts of our presence strewn everywhere, all the time. Even those primitive tribes in the Amazon or whatever see outlanders occasionally and our stuff. I bet they find our crap all the time and run across modern people here and there.

Ground observations – Those encounters of ships and entities on the ground, like the Ariel School are like, decades old. There are numerous reported “abductions.” But with all these cases there is virtually no video evidence.

Artifacts – Whether seen the air or on/near ground, where aren’t there more leave-behinds (debris, drippings, parts, etc)? Surely with all the sightings reported on this forum, there should be more “stuff” left over from the frequent flyovers, more than the government can scoop-up immediately.

It just seems like mostly what we get are apparent objects, floating or buzzing about, leaving nothing behind, and rarely coming down to our level. It leaves me with doubts about all this.