genea, translated as generation from the Greek, means familial connection, past, present, future. Thus, this genea shall not pass away is literally true. Those with familial connections to whom He was speaking still exist, they haven´t passed away.
Consider these things.
1.
Mark 9: 1 And he said to them, “Truly, I say to you, there are some standing here who will not taste death before they see that the kingdom of God has come with power.”
So the message here (and elsewhere in Mark and the gospels) is, Get ready, the Kingdom is at hand! It's happening NOW. It's about YOU!
2.
Mark 13:29 So also, when you see these things taking place, you know that he is near, at the very gates. 30 Truly, I say to you, this generation will not pass away before all these things take place.
So this is the same message, the same idea, the same sense of immediacy.
3.
γενεά basically means 'birth'. By association it can mean 'descent', hence 'family' and 'tribe'. But every translation I can find on the net chooses another of its meanings, 'generation'. Why is that, do you think?
You speak about The Kingdom, but I don think you have a clue as to what it is. Christ made it clear that the Kingdom existed at His time, yet he told Pilate that his kingdom wasn´t of this world.
As I mentioned in another thread just recently, in the NT 'The Kingdom of God' has two meanings:
First, ‘the Kingdom of God’ can mean the presently-living faithful, sometimes seen as faith itself as an entity:
Mark 4:26 And he said, "The kingdom of God is as if a man should scatter seed upon the ground,
Mark 10:15 Truly, I say to you, whoever does not receive the kingdom of God like a child shall not enter it."
Matthew 12:28 But if it is by the Spirit of God that I cast out demons, then the kingdom of God has come upon you.
Luke 10:9 heal the sick in it and say to them, 'The kingdom of God has come near to you.'
Luke 10:11 'Even the dust of your town that clings to our feet, we wipe off against you; nevertheless know this, that the kingdom of God has come near.'
Luke 11:20 But if it is by the finger of God that I cast out demons, then the kingdom of God has come upon you.
Luke 17:20 Being asked by the Pharisees when the kingdom of God was coming, he answered them, "The kingdom of God is not coming with signs to be observed;
Luke 17:21 nor will they say, 'Lo, here it is!' or 'There!' for behold, the kingdom of God is in the midst of you."
Romans 14:17 For the kingdom of God is not food and drink but righteousness and peace and joy in the Holy Spirit;
And second, ‘the Kingdom of God’ can mean a future establishment or condition:
Mark 1:15 and saying, "The time is fulfilled, and the kingdom of God is at hand; repent, and believe in the gospel."
Mark 9:1 And he said to them, "Truly, I say to you, there are some standing here who will not taste death before they see that the kingdom of God has come with power."
Mark 9:47 And if your eye causes you to sin, pluck it out; it is better for you to enter the kingdom of God with one eye than with two eyes to be thrown into hell,
Mark 10:23 And Jesus looked around and said to his disciples, "How hard it will be for those who have riches to enter the kingdom of God!"
Mark 10:24 And the disciples were amazed at his words. But Jesus said to them again, "Children, how hard it is to enter the kingdom of God!
Mark 14:25 Truly, I say to you, I shall not drink again of the fruit of the vine until that day when I drink it new in the kingdom of God."
Matthew 21:31 “Which of the two did the will of his father?" They said, "The first." Jesus said to them, "Truly, I say to you, the tax collectors and the harlots go into the kingdom of God before you.
Luke 7:28 I tell you, among those born of women none is greater than John; yet he who is least in the kingdom of God is greater than he."
Luke 9:27 But I tell you truly, there are some standing here who will not taste death before they see the kingdom of God."
Luke 13:28 There you will weep and gnash your teeth, when you see Abraham and Isaac and Jacob and all the prophets in the kingdom of God and you yourselves thrust out.
Luke 21:31 So also, when you see these things taking place, you know that the kingdom of God is near.
Luke 22:16 for I tell you I shall not eat it until it is fulfilled in the kingdom of God."
Luke 22:18 for I tell you that from now on I shall not drink of the fruit of the vine until the kingdom of God comes."
Acts 14:22 strengthening the souls of the disciples, exhorting them to continue in the faith, and saying that through many tribulations we must enter the kingdom of God.
1 Corinthians 6:9 Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither the immoral, nor idolaters, nor adulterers, nor sexual perverts,
1 Corinthians 6:10 nor thieves, nor the greedy, nor drunkards, nor revilers, nor robbers will inherit the kingdom of God.
1 Corinthians 15:50 I tell you this, brethren: flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable.
Galatians 5:21 envy, drunkenness, carousing, and the like. I warn you, as I warned you before, that those who do such things shall not inherit the kingdom of God.
2 Thessalonians 1:5 This is evidence of the righteous judgment of God, that you may be made worthy of the kingdom of God, for which you are suffering ─
(And there are a number of other uses of the term which are unclear:
Mark 4:11; Mark 4:30; Mark 10:14; Mark 10:25; Mark 12:34; Mark 15:43
Matthew 19:24; Matthew 21:43
Luke 4:43; Luke 6:20; Luke 8:1; Luke 8:10; Luke 9:2; Luke 9:11; Luke 9:60; Luke 9:62; Luke 13:18; Luke 13:20; Luke 13:29; Luke 14:15; Luke 16:16; Luke 18:16; Luke 18:17; Luke 18:24; Luke 18:25; Luke 18:29; Luke 19:11; Luke 23:51
John 3:3; John 3:5
Acts 8:12; Acts 19:8; Acts 28:23; Acts 28:31
1 Corinthians 4:20
Colossians 4:11)
What you don´t grasp is that the Spiritual kingdom ( The Kingdom) has always existed, and will be reconciled as the literal kingdom (The Kingdom) at the end.
See above.
This is the problem with superficial understanding, and cherry picking verses to make a criticism point.
If that's a problem, it's not my problem.
Exegesis is the method that must be used , line upon verse by verse to get clear understanding.
No, the document must be translated to find what it actually says. Once the words are clearly in place, arguments for possible alternative significances can be offered if they're based on evidence. If they're based on doctrine, that's simply requiring the text to conform to someone else's view, a perversion of the actual text.