You are missing the point and i would say you are doing that deliberately, but i actually do not believe that. It is because you are dense.
The plane WILL NOT be made ready for AF1 use, EVER, because as you say, it would take years beyond Trumps term to do so.
So the Military once they have possession of it will make the determination and agree with you and then because the plane is NOT staying with them beyond Trumps term and is being turned over to his library will just do what is logic and not start retrofitting it and instead just give it to Trump Library early.
So you are correct in one point but because you lack intelligence you do not connect point 2.
The military has no right to keep the plane beyond the end of Trumps presidency as the commitment they are making in taking it is to turn it over to Trump Library. So either they begin retrofits they KNOW will never be completed and thus are wasted time and money or they just REALIZE that, after doing an assessment and then give the plane over early without wasting that money as that is the only thing that makes sense, since it is going to Trump Library anyway.