As you well know, Jesus did not just use the word "genea". He used the phrase "this generation" (genea tauth). An important consideration.
E.g., in Luke 11:30 we read, “For as Jonah became a sign to the Ninevites, so also the Son of Man will be to this generation (genea tauth).”
Jonah was not a sign to every generation of Ninevites (the entire race). He was a sign to that generation only. And thus the parallel to Jesus’ reference to the Jews of His day.
This is how Jesus consistently used the phrase.
And, as I argue here the phrase has context and meaning to the Jews of that day. Jesus used the phrase consistently to refer to that generation of Jews. He was picking up on the phrase from the Old Testament (see Deut. 1:35).
Not really--and it's genea haute, fyi. It could just as easily mean "this race" as "this generation."
Jonah was not a sign to every generation of Ninevites (the entire race). He was a sign to that generation only. And thus the parallel to Jesus’ reference to the Jews of His day.
Actually, that reference works contrary to your intended interpretation, since it parallels "Ninevites" (a people) with genea, suggesting the latter is also in reference to a people rather than a period of time. In fact, Jonah was indeed a sign to future generations of Ninevites--they disregarded the sign, so God sent His judgment.
This is how Jesus consistently used the phrase.
Actually, the way Yeshua used the phrase is consistently ambiguous about whether He is referring to a people or a period of time, except where it favors the "people/race" interpretation. For example:
Mat 12:39 But He answered and said unto them, "An evil and adulterous generation seeketh after a sign; and there shall no sign be given to it, but the sign of the prophet Jonas . . ."He was picking up on the phrase from the Old Testament (see Deut. 1:35).1Co 1:22 For the Jews require a sign, and the Greeks seek after wisdom:
The phrase "this people" has equal grounding in the Tanakh (cf. Isa. 6:9), so again you're not proving your case--a necessary case, for preterism--that genea haute can only mean "this generation" and not "this people."
And on that note, I've got to go soon. I may have time for another brief exchange, but hopefully no one will take it amiss if I vanish for a bit.