Heaven is a place where “spirit bodies/beings” can live, like God and angelic beings. Humans, being flesh, can not survive there. Our composition is limited.

Earth is needed for us to live, grow and develop. Much like having a “uterus” where a zygote( fertilized egg) can survive before coming out of the womb after generally 9 months and live. We need “time for every season”Eccl. 3:1-8

Similarly, humans need time on earth to develop and receive the Holy Spirit for “spiritual development”, before being “changed in a twinkling of an eye”(I Cor. 15:52), becoming “spirit-composed bodies” at resurrection.