Science is one reason. Many people do really have a "god of the gaps" type of thinking. It is not really solid evidence for God's existence but it was real for many people. The bigger the scientific gaps the more people felt the need to believe in God. We still have gaps but they are a lot smaller. It takes some of the mystery out of creation when you can describe how things work physically. Like the conception of a child. We know what happens physically. We also know God creates a human soul when we create a human body. The physical process has become a lot less mysterious over the last few centuries. The spiritual process remains quite mysterious. It is tempting to just forget about it.
Another way technology has made faith harder is advances in contraception. Sexual morality was not always such a hard sell. People understood that sex leads to children so if you are not ready for children then one should abstain. The physical paralleled the spiritual so you just needed to understand one and the other followed. Now it is quite easy to manipulate our bodies so physical and spiritual don't match up. So you need to understand both or you are going to go wrong.
Then there is the mass media push of pornography. I can't imagine growing up in a world where movies didn't exist and printed material had poor quality pictures. The images that get burned into the mind of so many young men were simply not there. Lust is always an issue for men but not having that has got to make it a lot easier. How many refuse to believe in God because they don't want to embrace Christian sexual morality? Way more than will ever admit it. It is one of the biggest challenges to living the Christian life and it basically didn't exist 100 years ago.
The other way mass media hurts religion is to expose people to many foreign ideas. It used to be that just the educated knew about all the different ideas out there. They were able to process it all and keep their faith. But now we have every half-baked idea being thrown around in the public sphere. People lack the education to figure out why these ideas are not that impressive. It used to be church, home, and school. If kids got good solid teaching from those 3 sources there wasn't much else available. Now parents struggle to get 10% of their kid's music, TV, and computer to be Christian.
All these seem to work against religion. What is working in its favor? There really isn't much. Essentially when sin abounds then grace abounds more. We are made in the image of God. So at our deepest level we love the things God loves and hate the thing God hates. So as bad as the culture of death is, it is also good. Because people are innately pro-life. They can cover that up but they can't make it completely go away. It is in their soul. So the more Christianity becomes the lone pro-life voice in society the more the church is going to appeal to people.
The same goes for other types of evil. Some believe people are naturally sexually perverse. In a way they are. But at a deeper level they crave purity and desire to make sex an unconditional gift of self. So the choices are more stark. Technology as allowed us to put our worst foot forward. We have done that and made it obvious we need help. It is obvious because God has given us the ability to know good from bad. Think of Rom 1:18-20:
The wrath of God is being revealed from heaven against all the godlessness and wickedness of men who suppress the truth by their wickedness, since what may be known about God is plain to them, because God has made it plain to them. For since the creation of the world God's invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that men are without excuse.So it is good news and bad news. The good news is God has made things plain to us. The bad news is we are now responsible for now we respond to that revelation.