This is another way to answer your question about the length of the Divine Liturgy, and why it does not bother most people that it is as long as it is.
Many Orthodox Christians believe that this life is just preparation for something else that will come after we depart it. We believe that it will be an everlasting life in the Kingdom of Heaven. And we see the Kingdom of Heaven as being life with God and all others that are living this everlasting life with God our Father.
To help us in this preparation, the Son of God himself became one of us, and one of the things He did for us was to start His Church here on Earth. This Church can give us a taste of the Kingdom of Heaven if we let it. Many tell us the Divine Liturgy is very much like the Kingdom of Heaven. That hour and a half to two and a half hours is what eternity will be like after we depart.
So in our efforts, to become closer to God, we can use the experience of the Divine Liturgy, to help us experience Kingdom of Heaven here and now.
(I’m not a theologian, this is just my thoughts, I may be wrong)