There was no fruit being produced anywhere in the vineyard. The Lord recognized that. The separated branches that He had visited were able to produce covenant sons and daughters of God, only to fail to keep the covenant alive. "[N]ow all the trees of [the] vineyard are good for nothing save it be to be hewn down and cast into the fire." (5: 42.) That does not mean they aren't going to be preserved. They will, but they will suffer the wrath of God. Then they will come forth at the end of the season, and be placed in a position of Telestial Glory to dwell in the same condition as this fallen world. (D&C 76: 81-85.) From the Lord's perspective, that is undesireable. It is failure. It is tragic. This is the native condition this vineyard repeatedly lapses into, even with the Lord and His servant's continuing care. What more could He do, indeed! How often would He have gathered us, but we refuse. (3 Ne. 10: 5.)
Even when the Lord bestows peculiar advantages on the branches of His vineyard, the results are not dissimilar to what goes on elsewhere. Highly favored and greatly blessed people seem as indifferent to their salvation as those who inherit challenges and difficulties. (5: 43.) The Lord "cut down that which cumbered this spot of ground, that I might plant this tree in the stead thereof." (5: 44; see also, Ether 13: 1.) He provided the best spot in the vineyard by destroying the people inhabiting it. Then, as we shall see, He destroys the branches brought there once they also fail to produce suitable fruit.
The good spot was cleansed of the bad branches, yet the bad still overcame the good. (5: 45.) The Nephite civilization was, in the end, entirely overcome and destroyed because it failed to produce any more sons and daughters of God.
As the Lord surveyed the entire vineyard, He saw nothing but universal failure. There was no fruit able to be preserved against the coming season of judgment. The whole earth was worthy of destruction, because there were none whose hearts were sealed to the fathers in heaven, members of the Family of God, who could endure His presence at His return. In other words, there was no righteous branch living on the earth. All manner of fruit claimed to be good. All kinds of pretenders were claiming they were of God. They clammored "lo here!" and "lo, there!" and claimed they could deliver souls from hell. Yet no one was able to bring the living into contact with God, which was required in order for them to receive the "testimony of Jesus" promising them eternal life. (D&C 76: 51-55.) The Lord needed to begin over again. The vineyard was void of fruit-bearing trees. Despite this, the Lord reflected "it grieveth me that I should lose them." (5: 46.) The Lord takes the salvation of mankind seriously. It is His work. And when they fail, He grieves.
The Lord lists all He does to try to provoke His "tree" to bear fruit. He does not "slacken his hand" nor does he fail to "nourish" it. (5: 47.) He "digged," and He "pruned," and He "dunged" the tree. These efforts include sending the Light of Christ, the Holy Ghost, scriptures, prophets, angels, visions, dreams and signs in the heavens above and the earth beneath. He has done this continually for His vineyard. But these many gifts from God, and the great work He has done have failed to produce fruit. At last He poses the question to His servant: "Who is it that has corrupted my vineyard?" (Id.) A worthy question, indeed. The answer is surprising, because it does not require a devil to be involved.