Revelation is simbolic. The fact that them and the 24 old man, or that 144000 are in heaven, does not mean any of them will be in heaven. They will all be on earth. The king, Jesus will come back to earth, his asociates, will be on earth as immortal men. And they will rule over flesh and blood. The surprise for jw's will be that flesh and blood will continue to die in the 1000 kingdom Isaia 65:20 says people will live longer but grow old and die! People who never knew God will be reaurrected as flesh and blood and get a second chance and still die.
At the end of the 1000 years there is a second judgement. The last chance for flesh and blood to become imortals. After that there will be no chance and there will be only immortals. They will get a new earth.
The purpose of God is to make a new race of man, indestructible, imperishable and eternal. A man with whom He can have comunion and a close relationship.
The purpose of life is to have that kind of relationship with God, not to have a vain yard and a tree and a house. Those are conditions of flesh and blood humans in the millenial kingdom, but not the purpose of life!