The concept has been long secularized. Of all the things atheists complain about, I’ve never heard any gripes that they needed churches to tie the knot. But again, this was back when being married made a huge difference in what a pair was legally allowed to do. Now the only thing (off the top of my head) is income tax treatment.
It's still an intrusion into religion. Cities and states once banned trade on Sundays, too.
The trend is for less state involvement in religion, not more.