As I consider what is keeping people from responding to Christ these days, it seems to me that materialism is the biggest issue. Most materialists will deny that they even have this problem because they often associate this term with a love of money which they may not have... and it is easy to think you do not love something if you don't have much of it. But materialism is the belief that this material universe has always existed; as Carl Sagan articulated, "The cosmos is all there is, or was, or ever will be."
Even when materialists acknowledge the possibility that God directed evolution to bring about living things, they have a deistic view of God; that He just set things in motion and doesn't much care about what people think of Him. They deny that God created us for a reason and that failure to recognize our purpose to prepare for eternity comes with severe consequences. They justify their rationale with the retort, "why would a loving God send anyone to hell." But God does not send people to hell, people chose eternal separation from Him when they refuse to accept Jesus Christ as His provision for salvation; see John 3:18. The root problem of course is sin... loving yourself so much that you refuse to acknowledge any authority in your life other than yourself.
Materialists reject the simple logic of "Pascal's Wager" which challenges us to weigh the potential upside against the downside of believing the Bible assuming it really does turn out to be from God. Betting against the Bible being true has the severest of consequences while wagering that the Bible is true leads to eternal blessings. It is simply illogical not to take a chance on believing the Bible. Materialists insist on entertaining a myriad of potential explanations for the universe instead of recognizing the truth of God's Word for what it is: the Creator reaching out to His creation so that we may know Him.
Materialists see the negative trends of this world and are hopeful that things will work out OK anyway... they always have in the past; indeed, "all things continue as they were from the beginning of creation" (2 Peter 3:4, NKJ). But God poured out His wrath on the earth in the worldwide flood of Noah's day and has warned us about the time He will judge the nations during the Tribulation. Materialists do not recognize the evidence for the worldwide flood and instead hold to their belief that "the fossil record" was built up over great periods of time instead of the result of a single cataclysmic event. So materialists are headed for a rude awakening some day and indications are that this day is rapidly approaching.
The good news for materialists is that if they are still alive, it is not too late to "come out from among them and be separate" (2 Corinthians 6:17). We don't have to suffer the fate of the broad majority of this world (Matthew 7:13-14). Our mortal lives is a test to see who will turn away from our predisposition of putting ourselves ahead of God. The decision of where we spend eternity is ours to make... "unless you repent you will all likewise perish" (Luke 13:3).
As a former materialist for most of my life myself, I can testify that knowing Jesus Christ does indeed lead to an abundant life (John 10:10); even in the here and now. Those who don't know Him don't know what they are missing. It behooves everyone to, “taste and see that the Lord is good” as Psalm 34:8 invites us to do.