There seems to be professedly Christian musicians who do a 180, but then there're also musicians who go the opposite way and find God, sometimes late in their careers. There is a bit of scepticism about that, I've noticed. I'd never listened to Christian music (apart from hymns) until very recently, but I bought a couple of albums, some of Johnny Cash and George Jones's Christian stuff, I listen to it in the car on the way to and from work. I like the music, the George Jones stuff is catchy, like 'Will There Be Any Stars In My Crown'. Folk say that Jones is a hypocrite, and they question the genuineness of his conversion because making gospel music is undoubtedly a good way to make a fast buck, particularly in the US. I don't know. I'd prefer to give him the benefit of the doubt. Maybe he started off in a cynical way and he might've been touched in his soul when he thought about some of the words he was singing. That's between him and the Lord, and either way his eternal residence is fixed now.
I know this is off-topic, but one thing I will say about modern Christian music is that the vast majority of it doesn't seem to have much depth. There's a lot of repetition, and the lyrics, while they are mainly correct and in line with scripture, just don't seem to really show a great deal of knowledge of God. A lot of it seems focused on the believer, it's all "Jesus, You are so great, You did this for me, and that for me" etc. That's good, and we should absolutely meditate on everything that God has done for us - but there is more to Christianity than just that. It's really the mark of someone who's quite young in the faith that all the scope they have is thinking about what God has done for them. As we grow, we get a wider view. This wider view doesn't seem to be much represented in modern Christian music - or the stuff I've heard, anyway. When the impressions in the lyrics are so simplistic that they could've been gleaned off any Christian website, one almost wonders if the musicians are in fact believers at all, or if they're just in it for the money. That's possibly an awful thing to say, and it's most likely not true in the majority of cases, but one can't help wondering.
Another hobby-horse of mine is the way that, in modern music, divine Persons are never addressed using reverential language (i.e. thee, thou, thy...). However, since that language is hardly used by Christians at all nowadays - it's deemed "old-fashioned" - it's not surprising that it isn't used in music. It does put me off listening to modern Christian music, because I do find they lyrics jarring in that way.