qwerty first answer my question in brachos in the other thread – on the gemara you just learned for 10s of hours on this blatt, then ill discuss this gemara with you. it would help if you would read this gemara – the whole page then comment,
here in english:
With regard to the verse: “For I have taken you to Myself: And I will take out one of a city, and two of a family” (Jeremiah 3:14), Reish Lakish says: The meaning of this statement is as it is written, that only individuals will be spared and the rest will be destroyed. Rabbi Yoḥanan said to him: It is not satisfactory to God, their Master, that you said this about them. Rather, the merit of one from the city causes the entire city to benefit, and the merit of two from a family causes the entire family to benefit and be redeemed. Likewise, the Gemara relates that Rav Kahana sat before Rav, and sat and said: The meaning of this statement is as it is written. Rav said to him: It is not satisfactory to God, their Master, that you said this about them. Rather, the merit of one from the city causes the entire city to benefit, and the merit of two from a family causes the entire family to benefit and be redeemed.
also on that gemarathe maharal explains on that gemara of 1/300k that it means from all the jews who lived in all the generations, many died or were killed. so what will be left when moshiach comes will be 1/300k. nothing to do with only some jews being redeemed. so by techiyas hamasim the jews will multiply 300k times. because all the jews from all generations will come back