Why do a lot of Christian TV preachers sound like motivational speakers?

Probably because many of them are motivational speakers who preach a self-help gospel or prosperity gospel message. It's a bit of a contrast between the message of the Bible. Jesus tells us to expect persecution. Sometimes we experience suffering and hardships and this is not always the result of our own actions, think about Job. Having a lot of money doesn't mean that someone has a right relationship with God. In the Bible, there were Christians who had more and Christians who had less. The ones who had more, were expected to be good stewards of their money - to have enough to take care of their family and also have some money to contribute to the welfare of other Christian brothers and sisters, who were experiencing a time of need. Some people have no desire to work and want to be mooches. God tells us the ones who don't work will not eat. Sometimes seasons will happen in our lives when we the rain seems to pour down quite hard on us and that's when it is a great blessing to have the support from fellow brothers and sisters in Christ. God will not always give us everything we want. John the baptist was feeling a little resentful, because he thought Jesus would keep him from getting killed. Jesus said to John, blessed is he who is not offended in Me. God will do things according to His will. We can certainly present our requests before Him, but we must also know that it is not us who steers the ship.