Druidry is here and well-established, and continues with whatever “facts” are facing it. What we know of the druids comes from biased and/or invented second-hand reports. Whatever wisdom they left might be found in medieval sources and folklore, but not without heavy alteration over time and by the hands of Christian scribes. Any connection between archaeology and the druids is, necessarily, speculation. And yet modern Druidry continues unabashed.
Some druids will, like many, ignore the evidence, and carry on believing what they want (this is common enough, many still hold to Genesis over geology, and even new scientific theories must wait for the new vanguard to replace the old vanguard). Others will “lose faith” and go seeking for that fabled legitimacy elsewhere – they’ll just find the same, I reckon. And yet others will do something with the evidence and use it to see their traditions in a different and more honest light.
Fiction may not be true, but it can still be meaningful and inspirational. If this weren’t the case, all science fiction and fantasy would just shrivel up and die. And most religion too, I shouldn’t wonder! I’m reminded of what AMORC says about their history that it “may be divided into two general classifications: traditional and chronological. The traditional history consists of mystical allegories and fascinating legends that have been passed down for centuries by word of mouth. The Rosicrucian Order’s chronological accounts are based on specific dates and verifiable facts.”
“Traditional” accounts of Druidry may be found in Iolo Morganwg’s Barddas or Ross Nichols’ The Book of Druidry (a related account of the latter may be found here). A chronological account would be Ronald Hutton’s Blood and Mistletoe, which effectively dismantles the historical legitimacy of the previous two, but doesn’t quite strip away their value, bringing it more into focus, but only if viewed creatively, through the lens of Awen and applicability.