Your post here appears to be based upon the premise that all, or at least some, of the sensors are tracking all the targets. I'm sure your experience will have proved that is seldom the case, especially when the air situation is highly dynamic.
Oh my. So many false assumptions/assertions in two sentences. Where do I begin?
1. My experience is in a cockpit (F/A-18C) that was pretty advanced in the early part of this century and remains largely so today. The air picture in that cockpit was generated by the pilot's eyeballs which was fed data from two sources: looking outside and looking at an active RF (radar) display. That radar picture was updated manually by the pilot and fuzed with eyeball data in the pilot's head. That remains true of essentially every cockpit flying today.
2. F-35 has multiple onboard sensors beyond the pilot's eyeballs. It has passive RF, passive IR, and active RF. That sensor data is fuzed by the system and updated continuously and the updates displayed continuously to the pilot in a very intuitive format. In addition, the air picture generated by the airplane's onboard sensors are fuzed with
offboard data (like other F-35s, other fighters, AWACS, AEGIS, ground radar, etc.)
3.
No(!!), not all the sensors are tracking all the targets all the time. Each sensor has its strengths and attributes and each provides a PIECE of the air picture. The strength of the F-35 is that the airplane itself takes all the separate bits and pieces and fuzes them together to form a single air picture. The airplane as a system possesses a far more complete air picture than any single sensor and thru the (allegedly contradictory) helmet system, the airplane can communicate that air picture to the pilot very quickly and in a manner that the pilot can quickly and intuitively understand. So effectively the F-35 system forms a complete air picture (no other system does that, not even AWACS or AEGIS) and pipes that picture almost directly into the pilot's head.