As far as I know, both Lutherans and Calvinists are not subscribed to ritualistic pattern. The Great Apostasy article in Wikipedia, I believe, refers to the 'ritualistic' apostasy which were increasing in the period of pre-reformation.
Doctrine-wise, Luther and Calvin do not differ on great apostasy, as they hold on 'Sola Gratia, Sola Fide, Sola Scriptura'. The 'Apostasy' they fought was due to the greediness of the church at that time which deny those 3 principles as the foundation of Christian faith. In both Lutheranism and Calvinism, the important point of sacraments are to remember the work of Christ in this world, instead of doing them for the sake of the rituals. The same goes to the Christian holidays which are celebrated nowadays, they are acting as remembrance for the work of Christ.
Survivors of the persecutions were overly-influenced by various pagan philosophies either because they were not well indoctrinated in Jesus' teachings or they corrupted their Christian beliefs (willingly, by compulsion, or with good intentions but without direct revelation from God to help them interpret said beliefs) by accepting non-Christian doctrines into their faith. Latter-day Saints believe that many plain and simple truths of the gospel of Christ were, therefore, lost. (Wikipedia)
I quoted some of the Mormons understanding on the 'Apostasy' of the church. And, NO. Both Lutherans and Calvinists do not believe that the simple truths of the Gospel of Christ were lost due to the human inability to interpret the Scripture. Holy Spirit works, and to conform to this statement would means that we undermine the power of God (in this case via the persona of Holy Spirit), to help the church to understand the Truth.
At the very least, God has preserved the Truth from the time of Adam to Noah to Abraham to Moses to David to Christ to the early church. He, Himself, is the one and only Truth. After all, preserving the Truth and revealing Himself to the faithful and righteous has been his hobby for quite a while (i.e. Abel, Noah, Abraham, Isaac, Jacob, Joseph, I can go on and on with this). And, there wasn't any 'Bible' before Moses, they were all received the Truth orally, too, like the early church.