According to whatever context/reference point is being referred to, it is likely that there always IS an 'element' of "time" in using the word "generations" (there may be other "elements" that are being referred to.....tribal worship, or "the judges", events, etc.(to my understanding, both words are obselete for the true worshipper).
Presently, we are in the sabbath era, the age of eternity (so thar our sabbath rest in Jesus be eternal). Even though the concept of the "promised messiah" is spoken of all throughout O.T. scripture, the Jews did not choose to worship anybody but The Father only (Jesus was not GIVEN to the O.T. generations,but they could have decided on their own to do what King David when The Father said to David's lord "Sit at my right hand").
In the desert, God told them that they shall never enter His [sabbath] rest (they did not belong to the sabbath era of Jesus)
Luke 11:29
"This generation is an evil generation".
Seeking signs is like wanting PROOF (that desire destroys faith, even if you can, NEVER "prove" God).
Jesus came in the fulness of time (the completion and end of time). He ended the age of time and ushered in the age of eternity (a "generation" can only be relevant to "time").
Ephesians 1:10
"as a plan for the fulness of time".
Luke 18:30 and Mark 10:30
"and in the age to come eternal life.".
Our sabbath rest in Jesus is FOREVER/eternal. Every day, we live the present part of eternity. Our 'afterlife' destiny is going to be the same as our daily mindset. In Jesus, we no longer have MERE EXISTENCE, we have LIFE ("THE LIFE" eternal).
In John 14:6, Jesus said....
1) "I am THE WAY
2) ".....THE TRUTH" (God had Pilate say "What is truth?", the state delared the OBJECTIVE truth about Jesus's innocence).
3) "....THE LIFE".
"Generations" (functions of "time") were evil (God is not a function of time).