You are carefully ignoring the other meanings. You have to do that for Preterism to fit.
Let's test who's actually ignoring the meaning of "genea", and changing it to suit their own eschatological bias. Thayer's Greek lexicon does not list a verse for point number 2, which is where you believe Matthew 24:34 should fall. Point number 3 defines genea as a literal generation, in regards to Matthew 23:34, So it is very clear that you are ignoring the meaning of the genea as in interferes with your eschatological bias
Source: Strong's Greek: 1074. γενεά (genea) -- race, family, generation
Thayer's Greek Lexicon
STRONGS NT 1074: γενεά
γενεά, γενεάς, ἡ (ΓΑΝΩ, γίνομαι (crf. Curtius, p. 610)); the Sept. often for דּור; in Greek writings from Homer down;
1. a begetting, birth, nativity: Herodotus 3, 33; Xenophon, Cyril 1, 2, 8, etc.; (others make the collective sense the primary significance, see Curtius as above).
2. passively, that which has been begotten, men of the same stock, a family;
a. properly, as early as Homer; equivalent to מִשְׁפָּחַה,
Genesis 31:3, etc. σῴζειν Ρ᾽αχαβην καί τήν γενεάν αὐτῆς, Josephus, Antiquities 5, 1, 5. the several ranks in a natural descent, the successive members of a genealogy:
Matthew 1:17 (ἑβδόμῃ γενεά οὗτος ἐστιν ἀπό τοῦ πρώτου, Philo, vit. Moys. i. § 2).
b. metaphorically, a race of men very like each other in endowments, pursuits, character; and especially in a bad sense a perverse race:
Matthew 17:17;
Mark 9:19;
Luke 9:41;
Luke 16:8; (
Acts 2:40).
3. the whole multitude of men living at the same time: Matthew 24:34;
Mark 13:30;
Luke 1:48 (πᾶσαι αἱ γενεαί); ;
Philippians 2:15; used especially of the Jewish race living at one and the same period:
Matthew 11:16;
Matthew 12:39, 41f, 45;
Matthew 16:4;
Matthew 23:36;
Mark 8:12, 38;
Luke 11:29f, 32, 50;
Luke 17:25;
Acts 13:36;
Hebrews 3:10; ἄνθρωποι τῆς γενεάς ταύτης,
Luke 7:31; ἄνδρες τῆς γενεάς ταύτης,
Luke 11:31; τήν δέ γενεάν αὐτοῦ τίς διηγήσεται, who can describe the wickedness of the present generation,
Acts 8:33 (from
Isaiah 53:8 the Sept.) (but cf. Meyer, at the passage).
4. an age (i. e. the time ordinarily occupied by each successive generation), the space of from 30 to 33 years (Herodotus 2, 142, et al.; Heraclitus in Plutarch, def. orac. c. 11), or ὁ χρόνος, ἐν ᾧ γεννωντα παρέχει τόν ἐξ αὐτοῦ γεγεννημένον ὁ γεννησας (Plutarch, the passage cited); in the N. T. common in plural:
Ephesians 3:5 (Winers Grammar, § 31, 9 a.; Buttmann, 186 (161)); παρῳχημέναις γενεαῖς in ages gone by,
Acts 14:16; ἀπό τῶν γενεῶν for ages, since the generations began,
Colossians 1:26; ἐκ γενεῶν ἀρχαίων from the generations of old, from ancient times down,
Acts 15:21; εἰς γενεάς γενεῶν unto generations of generations, through all ages, forever (a phrase which assumes that the longer ages are made up of shorter; see αἰών, 1 a.):
Luke 1:50 R L (דּורִים לְדור,
Isaiah 51:8); εἰς γενεάς καί γενεάς unto generations and generations, ibid. T Tr WH equivalent to וָדור לְדור,
Psalm 89:2;
Isaiah 34:17; very often in the Sept.; (add, εἰς πάσας τάς γενεάς τοῦ αἰῶνος τῶν αἰώνων,
Ephesians 3:21, cf. Ellicott at the passage) (γενεά is used of a century in
Genesis 15:16, cf. Knobel at the passage, and on the senses of the word see the full remarks of Keim, iii. 206 (v. 245 English translation)).
God's message in Scripture was not solely directed at the immediate listener it was for every generation equally. He refers to man as "you" often, when speaking to His people. We can apply it to our lives on an ongoing basis.
the temple destruction is included in "all these things". So you believe you will see the destruction of the literal temple in Jerusalem in your life?
Matthew 24:33 So also, when
you see all these things,
you know that he is near, at the very gates.
You don't believe the "you" in matthew 24:34 applies to the 1st century generation that experienced the destruction of the temple?