A lot of religious writing describes how overemphasis on history is a sign of trouble. Some of this is because of the dangers of, say, churches taking too much pride in their past accomplishments, and (perhaps) neglecting the present. Another component is Protestantism's distrust for tradition, perhaps lingering echoes of the break with Catholicism.
Quakerism has a complicated relationship with its history. That history is itself complicated, with incredible early inspirational fire, a period of relative calm few historians seem to defend, and then a variety of schisms. There is deliberately no central creed Quakers subscribe to. Historic documents sometimes fill that gap, often pulled, like biblical proof-texts, out of their original historical and textual contexts.
There is a bigger problem, however: Quakerism is a religion based on experience, an experience many people don't think they've had. What does contact with the Light accomplish? How have Quakers been changed by their faith? What might make a skeptic think that there's something different going on in Meeting for Worship than a very quiet meeting of a Society for Ethical Culture chapter?
Frequently, the easiest way to answer these questions is to point to past Quaker experience. Not just what people say they've found or felt, but what they've done and how it connects to their account of what they've found or felt. Early Quakers' perseverance under persecution, dying for their cause while feeling they were working for the Lord, is one example. John Woolman's combination of Quietist faith and his ministry against slavery is another, as is Elizabeth Gurney Fry's work on prison reform, the efforts of conscientious objectors, and the work of Quakers up to the present, including Tom Fox.
This rich past informs our present, promising more than an hour of peaceful contemplation at Meeting. Different branches of Quakerism emphasize different aspects of that rich past, and there is certainly more than enough material for them to find parallel but different tellings of the same story.
There's still a pull, though, toward the idea that Quakerism's past should not determine its present. Early Quakers felt that Christianity, itself a break with the Jewish telling of the past, had accumulated its own problems from which Quakers were freeing themselves. Arguments over the degree to which Quakerism should be Christian (Evangelical, Trinitarian, Unitarian, or...) or not seem to explode especially well over which aspects of the history are relevant to modern Quakerism and which should be left as of value only to their participants.
Some of that, as in other churches, be about thinking positive, avoiding issues that might not be such fun to discuss, or which might break an important argument. Some of that may be because the issues involved make us doubt our predecessors, forcing us to sift through perhaps unsightly past context. And some of that comes from the concern that Quaker history, while fascinating and inspiring, shouldn't be used to limit the possibilities of Quakerism might become.
Personally, I find reading Quaker history to be inspiring even when - maybe especially when - I find Quakers behaving in ways that might not live up to the perfection we hope of our predecessors. We can remember that like us, they were humans grappling with the Light, with the challenge of building relationships where we ourselves are in this world outwardly while communing inwardly with a holiness transcending our humanity. Powerful inspiration leads to deep questioning and uncertainty, and often to amazing deeds performed not simply because of personal conviction but because of humility - this is what has to be done, not just what I think is right.
Quaker history is not an appropriate stick to use against people who claim the name "Quaker" while breaking with the past, in whatever direction. I do think, however, that reading Quaker history with a mind open to the possibilities of finding the experiences of the past once again in the present can lead to new (yet old) opportunities. We live in times where we're taught to doubt claims of experience beyond the five senses, or claims that can't be proven in the laboratory or the marketplace. Looking to the past may help us reclaim what many of us have lost.