I believe Samson and Solomon were saved. Even the thief on the cross was saved, too. However, God does not call us to live like the devil and then hope to repent in the end at the last second. Yes, there are those who repented in the end of their lives and were saved. This shows God is sovereign and knows a person's hearts and futures. But this does not change the fact that God (Christ) does not call and desire His people to walk in holiness and his good ways. That does not mean some will fall away from the faith due to persecution and the cares and the riches of this life (without repenting before they die). The Scriptures say, without holiness, no man shall see the Lord. That's a fact of Scripture. If a believer expects to outsmart God and they desire to repent in the end like a Samson and or a Solomon, then they are not going to make it. One has to have a pure heart before God and be open and honest before the Lord. Yes, you may not see it on the outside in all cases who is saved and who is not saved, but nobody can live in unrepentant sin and be saved. It doesn't work like that. So no. Nothing has changed. A believer has to live holy and follow the commands of Jesus Christ. Yes, God's grace is there for believers if they sin, but we have to realize that those that are Christ's have crucified the affections and lusts. In time, the true born again believer will grow and learn their lesson. Sometimes it will be at the end of their life and other times it is not. But holiness is not an option of a mark of being a true believer.
Holiness is the end result and goal for all true believers. It's not an option if one is truly of the Kingdom of God. For God is good. He is not evil. Meaning, evil people who like their sin more than God will not be in Heaven.