A likely scenario:
The Protestant mainline denominational churches have already succumbed to Secular Humanism and belief in big government, the nanny state. When govt. coercion or worse hits the Catholic Church and the smaller evangelical and fundamentalist churches with full force, the smaller churches(not Catholic) , the individual pastors/preachers/reverends will have to make a decision to either have smaller congregations and risk not paying bills and closing or adjusting their message and adjusting their preaching to new cowed wider audience, to the new standard...capitulation! This will happen as most of these smaller congregations are not part of a group where the weaker congregations are being supported financially by the group.
Protestanism in the main will fold.
Of course there will always be heros and martyrs, but financial realities and being of the world and in the world dictate alot of things.
Actually, from what I have seen the opposite will be true. It is the ‘mainline’ churches that are closing, the Evangelical churches are growing. Financially, some will fold but not all of them, not by far.
Christians are looking for churches who will not compromise and are leaving those that have already.
I know many pastors who will give up their non-profit status and continue to speak the truth, and financially they are stable.