God created the angels perfect. Perfect does not mean immortal.
Adam had human perfection and that too does not mean immortal.
In order for Adam to live forever would be under the condition of obedience.
In order for angels to live forever they would also have to obey their Creator.
Angels were created to remain in the heavenly spirit realm.
Adam was created to remain in the earthly realm of physical existence.
Angels are to do God's will for them in heaven or the heavenly realm.
Satan at first was a perfect angel meaning he could only do wrong on purpose. Satan and some other angels joined him in disobeying God.
Jude verse six talks of those angels as forsaking their original position in the heavens. Those angelic 'sons of God' (Gen 6:2,4) materialized in human form, and the hybrid children they had with earth's daughters were nephilim (fellers) mighty ones (verse 4) bullies or tyrants whose wickedness made matters even worse. The Flood caused the materialized bodies of those 'fallen' angels to be destroyed. Since they do not die as we die, for the time being, they are held in or imprisoned in what is termed 'darkness' in Jude six.
So all perfect creation because of having the gift of free will can choose to obey or disobey. Disobedience has proved to result in, not peace on earth, but violence. God created all to be exactly doing what we should be doing in obeying God's Golden Rule or as James (2:8) called it the kingly or royal law.