Where is "set up" found in the Olivet discourse?
It is not, that is why Jesus is not talking about 70AD as the end, or the Second Coming. 70AD was only the destruction of the Temple and Jerusalem and it was not even fully disassembled. Jerusalem and the foundation are still there today.
The walls of Jerusalem were built back, even the sealed eastern gate, was built backed sealed. Daniel said it was set up, but that happened in 167BC, 237 years prior to the Temple being destroyed. That is about the amount of time the US has been a nation. Not that long.
The part of Daniel that John uses in Revelation 13, is the point that an earthly system will be in place and a FP will arise out of this system, changing religion as we know it. A FP similar to the one who set up the AoD in 167BC. People are still trying to point to a system similar to 70AD, but Jesus and John were pointing to the prophecy that was fulfilled in 167BC. NOT 70AD. The only thing that happened in 70AD was millions of Jews were slaughtered or taken as slaves. The Temple burned to the ground. Jerusalem was without walls for hundreds of years.
The rest of the OD, is about the second coming that has not happened yet. When the Lamb returns, religion will take a huge hit. Satan will have to set up a new one. This new religion will cause humans to be eternally cursed by God with the mark 666. Forever removing their names from the Lamb's book of life. This will be a very conscientious choice, not by faith in God, but the rejection of seeing God physically on the throne on earth. Even knowing that God could destroy them, they still choose to worship Satan over God.
Even God's chosen people at Mt. Sinai in the presence of God on the mountain, still built a false idol and worshipped it. How much more those who reject God, will in the near future, reject God to His face. This is what Satan and his FP will do when given the chance. They will make it easier economically to worship Satan, and reject God. God will remove everything that points to Salvation and the Atonement, even the Lamb and the 144k, and let humanity feel what worship to Satan entails. Only 2 human witnesses will have to endure this time of God removing His presence from the earth. This time it will not be a few seconds like the Cross. It will be for a fixed 42 month period.
God will allow, for 3.5 years, His Atonement to be cut off, and no longer a reality, until Christ returns on a white horse and kills the rest of humanity at the battle of Armageddon.