The Hebrews author summed up his argument: Jesus is a great high priest. He serves in heaven, the reality of which the earthly tabernacle was a sketch. Jesus mediates a better covenant founded on better promises.

The New and Living Way | Episode 18 | Hebrews 8:1-6

Now in the things which we are saying the chief point is this: We have such a high priest, who sat down on the right hand of the throne of the Majesty in the heavens, a minister of the sanctuary, and of the true tabernacle, which the Lord pitched, not man. For every high priest is appointed to offer both gifts and sacrifices: wherefore it is necessary that this high priest also have somewhat to offer.

Now if he were on earth, he would not be a priest at all, seeing there are those who offer the gifts according to the law; who serve that which is a copy and shadow of the heavenly things, even as Moses is warned of God when he is about to make the tabernacle: for, "See," saith he, "that thou make all things according to the pattern that was showed thee in the mount."