Phone cameras have improved in resolution but their optical zoom hasn't gotten much better. The Chelyabinsk meteor is easy to see without any zoom because of the contrail and glow from burning in the atmosphere, but the UFOs that people claim to see don't leave any signatures. They're often reported as just shapes moving in strange ways or balls of light. The few witness testimonies I've seen often estimate the size of the UFO being smaller than a commercial airliner, I believe David Fravor said the Tic Tac was about the size of an F-18 hornet. If they also move as fast and erratically as people often claim, it's not that surprising there isn't more photographic evidence.

And there actually are quite a few photos and videos captured of UFO phenomenon, but they get posted on obscure areas of social media and never make mainstream news. The videos are often debunked as weather balloons, flairs, or something else prosaic. In some cases the debunking theory is confirmed because e.g. we can confirm that skydivers with flairs were in the same region as the video was taken. In most cases it's just a video of a small object in the sky and there's no way to confirm what it is.

Re: NORAD, Jacques Vallee claimed in a Joe Rogan interview that (either the ARTCC or NORAD) do see thousands of objects on radar every month that get classified as "uncorrelated targets" and are ignored because they don't show any inbound trajectory toward the US.