In my experience, church hopping happens mainly among churches which are anti-creedal and anti-confessional. It is very rare for a Lutheran who holds to the tenets of the Lutheran confessions to become, say, a Baptist. Or for a Calvinist to become, say, a Methodist. The historic Protestant churches which very heavy on catechesis and making sure that their disciples understand the beliefs the church confessed. The aforementioned traditions will generally only lose those members who were nominal.
In contrast, non-denominational churches have a high turnaround rate because many of their members do not have formal theological understanding. So, they will go from one church to another based on their needs; daycare, children’s church, music programs, etc. It’s very rarely doctrinal.