Literally millions of people have been exposed to Christ through our institutional churches. The problem is that what happens there so turns them off that they are lost to Christianity for the rest of their lives. They equate church with Christianity, and find church to be disagreeable, and so reject Christ.
It’s like we are vaccinating them from ever considering Christ again. A vaccination is made from dead and powerless organisms, that, when injected into our body prevent us from contacting the real thing. That’s exactly what we are doing to the lost around us. We bring them into our churches, and it turns them off. They equate church with Christianity, and then become immune to the real power of Christ.