To be honest, in 50 years Protestantism will be in more of a mess. While the LCMS will probably stay strong (much like the catholic church, they seem to have good doctrinal authority in their church), mainline churches will continue to see a decline almost to the point of irrelevancy. What i see as the big thing though is that evangelical churches (not evangelicals themselves) will decline. I once heard an evangelical friend of mine once say how presbyterians and methodists were really good biblical denominations. Anyway, my feeling is that those in charge on current evangelical churches will get too liberal and people will leave to either found their own churches, join churches who have actually stayed the same in teaching, or the whole “I don’t need religion, I have jesus” movement will continue. Sadly I see that movement gaining ground, especially amongst evangelicals who will be saved, but then only go to church infrequently and will say “but I follow christ, I don’t need church”. The hope for me is though is that Catholicism will attract people The only area i see catholicism struggling is with young people. Hopefully though they will return later, or better yet, be helped by better catechism and stay lifelong members.