May I add something here.
Those on the rocky ground are the ones who receive the word with joy when they hear it, but they have no root. They believe for a while, but in the time of testing they fall away. 14 The seed that fell among thorns stands for those who hear, but as they go on their way they are choked by life’s worries, riches and pleasures, and they do not mature. luke8:13&14
In the first example, people made a commitment, they received the word with joy, and went on their way. But, because they made a shallow commitment they fell away when things got hard. Now, you would have to turn scripture on its head to say those people had not been placed in a saved state. If you go on your christian way, and then fall away, you obviously fell away from the faith.
But in the next example, we see people become christians, but they keep getting side tracked from the path by lifes worries, riches and pleasures, as many of us do at times get side tracked from the path we should be on by one thing and another. Jesus did not say these people fell away, but rather they did not mature in the faith. For you mature by evermore practicing right from wrong
So to sum up, the people who made a shallow commitment did walk away from the faith, whilst others, who kept getting sidetracked from firmly staying on the path they should have been on did not. We could say, no OSAS for the first group, But OSAS for the second group