
We are more spiritually starved now than they ever were, then. The majority of people had more Scripture memorized, because of the Mass, than do today, in an age of literacy.
When did these groups ever “join up” with each other?

For the first 150 years of the Reformation, they were all busy burning each other at the stake.
As far as I can tell, they are even
more fragmented than ever, right now, although at least they are not burning each other at the stake any more.
There are only two congregations of Waldensians left in the world (which stands to reason, since they require their clergy to work for free, and not to own any property of any kind, including books, clothing, etc., which they are required to borrow from members of the congregation), and the Anabaptists have fragmented into everything from the Hutterites to the Amish, to the Mennonites, to Plymouth Brethren, and various flavours of “non-denominational,” etc.