I think the worst fate that falls on modern people is that they usually get more rebellious, sinful, and skeptical only in their post-highschool years (usually college for most). The time of "sowing your wild oats" or whatever you want to call it.
In retrospect, I thank God that he saved me when I was still a teen. I was pretty much a delinquent before that. I was involved with gangs, drugs, etc.. I kind of was already up to no good by 10, and quickly reached rock bottom, close to death from others or myself, already at 17. And as bad as it all was, I'm starting to think it's worse if you grew up in an opposite fashion. One of conforming to society, family, school or you were just an all around boring person (boring in a good way), AND THEN only lashed out the moment you got to college or joined the military or what have you. This seems to be a path that many fall into, rather than mine where I got it out of my system early on. Around this time, many start experimenting with sex, drugs, drinking, and are just open to new ideas (often bad ideas). The main problem with this is that it's all associated with their "adulthood" - and there's a certain pride with this, that keeps them from ever seeing their error. These people then go on, maybe graduate, get jobs, and become "adults" with all of these other experiences that are also associated with their "adulthood". They continue on the same path well into their 30s, 40s, 50s, or more with their careers. Their sexual tastes get increasingly more strange, their relationships more dramatic and destructive, they end up in careers in business that's unapologetically predatory, or they become "public servants" and "public intellectuals" who are literally hellbent on destroying society and especially the Church. They all end up becoming more more blasphemous, more predatory, more degenerate, and more criminal than even I was in my gangster days. And moreso than many hardened criminals you see in prison right now - who are often receptive to the Gospel too. The worst thing is the level of pride and stubbornness. They're unable to change or admit to any wickedness, because they also associate all of their behaviors with adulthood and part of them "growing up". For me, at 17, I didn't have any pride left. I hit rock bottom and God was able to tell me the Good News of Christ. It was just the right time to see Christ with childlike appreciation. And in his own words, "Amen, I say to you, unless you are converted and become as little children, you will by no means enter the kingdom of heaven." - Matthew 18:3
I'm afraid there's little hope for most people. You're better off just preaching the Gospel to those who know they're lost.