The "ALL" of verse 32 includes what was also just referred to in verse 24. That was not finished/completed/over in 70ad.
I mean this with all due respect but I think, like many futurists, you are desperate to deny what the Scriptures actually say. Jesus says ALL those things will happen to THIS GENERATION, His contemporaries.
Verse 24's "Time of the Gentiles" is the siege of Jerusalem which ended in 70 A.D. The Olivet Discourse is not the only place where Jesus says He is returning in His generation. He also says it in Matt 10: 17-23 and Matt: 16: 27-28.
Matt 16: 27-28, "For the Son of Man will come in the glory of His Father with His angels, and then He will
reward each according to his works.28 Assuredly, I say to you,
there are some standing here who shall not taste death till they see the Son of Man coming in His kingdom.”
How do you answer these verses? They prove that a future second coming of Jesus is false. He already came back in 70 A.D. just like He promised. There is no answer for Matt 16 according to the futurist paradigm. It proves all futurist eschatologies to be false and as you can see it isn't just one passage that says it but multiple.