Just piss poor situational awareness outside the cockpit. Too much focus on the landing point and not looking all directions for traffic and possibly lack of good communications. I think the other comment mademeant left base not crosswind.

Somewhat close, but really no big deal inspite of the obvious incursion of the other plane. I'm not sure why this video is even included here. I see these things frequently at uncontrolled strips - I wouldn't've bothered to send it in.

like in 1993

Unfortunately this happens very often. The pilot with the video seems to be on a very long, straight-in final. An aircraft left crosswinds below him and one is seen on short final below him. No communication is heard.