Are the dead forgotten by God? What's the point of the resurrection of the dead if they are forgotten?
Please apply some critical thinking skills when you read. Each of the words that are written right where they are are not difficult to understand.
One principle to understanding the Scriptures is that they must be understood in their context. There is always an immediate context, often a remote context, and there is also always the entire context of all the Scriptures put together.
Jesus Christ admonished in John 5:38:
Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.
I don't see that Jesus at any time admonished his followers to consult theologians, philosophers, scientists, or Harry Potter. If the words are abundantly clear (as they are almost all places in decent translations), and there has been no forgery (deliberate or accidental), then just read what's written.
You should, of course, be careful that the version of the Scriptures you pick up is not just mostly crap.
The KJV: "for the memory of them is forgotten" may just as well be translated "for their memory is forgotten". The beginning of the verse states the dead "know not anything". If you have no memory, exactly what would you know?
Conversely, if you know not anything, exactly what then would you remember?
If your own memory is forgotten, what could you possibly remember? In one sense, the statement is a tautology. In our common English we might say "his own memories are lost", "he has no memory", or perhaps "he remembers nothing".
Moses is dead but not forgotten by others, isn't he? Among men a man may be forgotten, but no one is forgotten by God, either while they live or while they are dead, awaiting a resurrection.
When a person dies, he enters the state of death. Whatever was is his memory is no longer remembered by him, right? It has perished. What does one keep in his memory? Among other things:
Ecclesiastes 9:6
Also their love, and their hatred, and their envy, is now perished; neither have they any more a portion for ever in any thing that is done under the sun.
The dead aren't living: they aren't working, producing, loving, hating, envying. They aren't remembering that they ever did so. Have you ever seen a dead person do any of these things?
Verse 4:
For to him that is joined to all the living there is hope: for a living dog is better than a dead lion.
A dead person does not even have hope! He cannot hope. To have hope you've got to keep something in your memory to believe - the promise of a better future. Since a dead person has no memory, he isn't looking to resurrection from the dead in the future, for instance. He's dead and hoping is not something dead people can do.
Psalm 6:5
For in death there is no remembrance of thee: in the grave who shall give thee thanks?
Well, dead people aren't giving God thanks, either. That is one of the great tragedies of death. However, God has a wonderful plan to fix it.
Adam started the whole death thing among mankind. Jesus Christ is God's plan to sort it all out, and fix the problem. The promise of Christ followed immediately upon the heels of Adam's fall (see Genesis 3:15). The details were progressively revealed. What a kind God!
Psalm 116:15
Precious [costly] in the sight of the LORD is the death of his saints.
It was and is never God's intent or desire that people die. It costs God something each time someone dies. He doesn't like it any more than you do, I'm sure.
Ezekiel 19:32
For I have no pleasure in the death of him that dieth, saith the Lord GOD: wherefore turn yourselves, and live ye.
God's arch enemy, the Devil, is the one holding the power of death.
Hebrews 2:14
Forasmuch then as the children are partakers of flesh and blood, he also himself likewise took part of the same; that through death he might destroy him that had the power of death, that is, the devil;
Hebrews 2:15
And deliver them who through fear of death were all their lifetime subject to bondage.
Bondage through fear of death is the common or natural state of so much of the world, it seems. It explains why people do some of the otherwise inexplicable things they do.
In Jesus' time, religious and political people were happily working in concert with God's arch enemy.
Matthew 27:1
When the morning was come, all the chief priests and elders of the people took counsel against Jesus to put him to death
Consider what I say. In the present day, in the US at least, putting someone to death isn't so easy. So God's enemies employ every practical tactic they can to do as much damage to God and God's people as possible. If they did it to Jesus, what would restrain them from doing as much to his followers?
Chief among their tactics is to destroy the credibility of God's word in people's minds, I'd say. Because by it, God's word, people are saved and delivered from death.
There is much in the Bible concerning death and the state of death because, besides gravity, it is perhaps the biggest problem for all of us ;) The promise of God, though, is that in the end:
Revelation 21:4
And God shall wipe away all tears from their eyes; and there shall be no more death, neither sorrow, nor crying, neither shall there be any more pain: for the former things are passed away.
Verse 5
And he that sat upon the throne said, Behold, I make all things new. And he said unto me, Write: for these words are true and faithful.
Along with that...
Revelation 21:1
And I saw a new heaven and a new earth: for the *first heaven and the *first earth were passed away; and there was no more sea.
... there are many more promises of God. What a wonderful, kind, and loving God!
2 Peter 3:13
Nevertheless we, according to his promise, look for new heavens and a new earth, wherein dwelleth righteousness.
* "first" should "former". The reference is to the second heaven and earth, the one in which we presently live.