First - from what I've seen, evangelicals in general boil conversion down to praying a prayer, and Baptists are no different. And most times that I've seen, it's totally independent of the message of the cross. Now, I don't say that to derail the thread. It's simply the truth as I have observed churches.
I have seen this and can affirm your observation.
Second, also from observation, after a so-called "prayer of salvation", most people aren't being taught biblical doctrine in their churches. The substance of teaching is bible stories and behavioral badgering.
"Bible stories and behavioral badgering" is the perfect way to describe the way I was raised in church. When I faced serious questions in my first semester of college (actually, not from anything in school, but from a family member), I had no intellectual anchor. All I had were a handful of oft-repeated Bible stories, a couple of powerful experiences (feelings), and a general sense that God was real. But I recognized that feelings came and went and Bible stories might not be true. A five minute conversation turned me immediately into an agnostic. Now, I didn't stay agnostic, I needed to know. So I began to figure of what was true on my own because I knew that if I mentioned my concerns at church, I would be shunned and condemned, just as the family member with whom I had the conversation. The massive condemnation he received from asking uncomfortable questions as a teenager, helped turn him into an angry atheist.
My story turned out much differently, because I purposely avoided asking for help in seeking God from the church.
So there's nothing to grab somebody and hold on to them. And when younger people encounter that type of surface-level appeal to the flesh, it's only gonna keep them for so long.
Yep. You are hitting the issue squarely on the head.
...take a good look at the parable of the soils, from the perspective that the second and third soils represent genuine believers, and you will truly understand why believers are not maturing - and many are falling away.
I am one who believes that only the good soil, the fourth soil, represents genuine believers. The rest may be earnest, but they have not produced any fruit as a result of the seed taking hold. I think contemporary churches hold to the idea that the second and third soils are genuine believers because it justifies the lack of God-honoring fruit on display in their congregations. But a tree is known by its fruit. It will occur naturally.
That being said, there may be genuine believers in the congregation that are essentially dormant because they have not been given the complete gospel messing that involves training in the teaching of Jesus, and do not even know it is possible to follow Jesus in a practical and effective way upon this earth in this present life. When that message is presented consistently and effectively, those who are genuine believers will gladly receive the rest of the gospel message. Too often the gospel message is corrupted to simply be a theory of the atonement and a promise of heaven and fire insurance from hell. That's the message I heard as a child, well into my adult years until I started preaching the full gospel. I am now fortunately at a church where the pastor understands this and preaches the whole counsel of God.