When Charles Finney died in 1875 the holiness movement split 25
different ways.  The result was a split between the Methodist
understanding of the social gospel and protecting our evangelical
heritage. Can you explain the dynamics at work in this?

Most denominations are changing rapidly in recent decades so 1875
concepts are almost irrelevant. Typically the sermons are based more
on the beliefs of the paster than the denomination affilation.
Exceptions are Jehovah wittnesses and Mormons = The Church of Jesus
Christ of Latter-day Saints and a few others.