Why was the 5 Star Rank Done away with after Omar Bradley died in 1981? Why not have 5 Star Rank brought back since all of this fighting ?

We had 5 stars in WWII to deal with other country officer's (Field Marshall's, Army Commanders, who were equal to or out-ranked our 4 stars.

Because it's not needed. We have enough GOs in the military. We have 42 Active Duty 4 star GOs alone. The Army alone has 200 some odd GOs total.

The 5 star rank is reserved for a major war only. Usually for a very senior commander who commands over several nations military. Ie. WW ll and Korea.