The parable of the fig tree is about the generation that will not pass away without witnessing what Jesus spoke about in Matthew 24:15-31, which includes His return.
Is that why it was cursed forever by Christ?
How did the authority of the priesthood pass from the Mosaic priesthood to Christ (Galatians 3:13; Hebrews 7:12)?
Was it temporary or forever?
15 And when the chief priests and scribes saw the wonderful things which He did, and the children crying in the temple, and saying, Hosanna to the Son of David, they were angry.
16 And they said to Him, Do you hear what these say? And Jesus said to them, Yes, have you never read, "Out of the mouth of babes and sucklings You have perfected praise?"
17 And leaving them, He went out of the city to Bethany, and spent the night there.
18 And returning early to the city, He hungered.
19 And seeing a fig tree in the way, He came to it and found nothing on it except leaves only. And He said to it, let no fruit grow on you forever. And immediately the fig tree withered away.
20 And when the disciples saw, they marveled, saying, How quickly the fig tree has withered away!
23 And when He had come into the temple, the chief priests and the elders of the people came to Him as He was teaching, and said, By what authority do you do these things? And who gave you this authority?
24 And Jesus answered and said to them, I will also ask you one thing; which if you tell Me, I likewise will tell you by what authority I do these things.
25 The baptism of John, where was it from? From Heaven or from men? And they reasoned within themselves, saying, If we shall say, From Heaven, he will say to us, Why then did you not believe him?
26 But if we shall say From men, we fear the people; for all consider John as a prophet.
27 And they answered Jesus and said, We cannot tell. And He said to them, Neither do I tell you by what authority I do these things.
The rest of the chapter consists of Jesus telling parables about the priesthood and the kingdom and the authority of the Kingdom being taken from them and given to a nation bearing the fruits thereof.
45 And when the chief priests and Pharisees heard His parables, they knew that He spoke of them.
43 Therefore I say to you, The kingdom of God shall be taken from you and given to a nation bringing out its fruits.
19 And seeing a fig tree in the way, He came to it and found nothing on it except leaves only. And He said to it, let no fruit grow on you forever. And immediately the fig tree withered away.
43 Therefore I say to you, The kingdom of God shall be taken from you and given to a nation bringing out its fruits.
"But you are a chosen generation, a royal priesthood, a holy nation, a people for possession, so that you might speak of the praises of Him who has called you out of darkness into His marvelous light; you who then were not a people, but now the people of God, those not pitied then, but now pitied." -- 1 Peter 2:9-10
43 Therefore I say to you, The kingdom of God shall be taken from you and given to a nation bringing out its fruits.
11 Therefore if perfection were by the Levitical priesthood (for under it the people received the Law), what further need was there that another priest should rise after the order of Melchizedek, and not be called after the order of Aaron?
12 For the priesthood being changed, there is of necessity a change made in the law also.
13 For He of whom these things are spoken belongs to another tribe, from which no man gave attendance at the altar.
14
For it is evident that our Lord sprang out of Judah, of which tribe Moses spoke nothing concerning priesthood.
15 And it is still far more evident, since there arises a different priest after the likeness of Melchizedek,
16 who is made, not according to the law of a fleshly commandment, but according to the power of an endless life.
17 For He testifies, "You are a priest forever after the order of Melchizedek."
18 For truly there is a putting away of the commandment which went before, because of the weakness and unprofitableness of it.
19 For the Law made nothing perfect, but the bringing in of a better hope did, by which we draw near to God.
20 And inasmuch as He was not made priest without an oath
21 (for those priests were made without an oath, but this one was made with an oath by Him who said to Him, "The Lord swore and will not repent, You are a priest forever after the order of Melchizedek,")
22 by so much was Jesus made a surety of a better covenant.
23 And they truly were many priests, because they were not allowed to continue because of death;
24 but He, because He continues forever, has an unchangeable priesthood.
We will never go back to the Levitical priesthood. The fig tree was cursed by Jesus forever.
Understand the meaning of the cursing of the fig tree instead of trying to force scripture to comply with your own theories.