"How long will it be until we start seeing judges who have at least some passing knowledge about technology?"
The answer is they exist already. "They" being judges who have at least "passing knowledge." The real question is: when are there going to be enough of them so that a modicum of knowledge about how technology works becomes the norm. I don't know. I'm still waiting for it to be the norm for judges to use common sense in deciding cases.
But that raises an interesting point. If you have no basic understanding of how technology really works then what sort of "common sense" would you, as a judge, apply? The world is changing at an ever increasing rate [see this], and law's speciality has never been to keep up with change. Rather, its time-honored role has been to formalize rules that represent a consensus solution (i.e. one that a significant part of the population can agree is correct). Consensus solutions obviously take time. Lots of time. In short: as the pace of change picks up, our justice system (as it is presently constituted) will pose an ever-increasing barrier to meaningful change. And groups and organizations that exploit the entrenched resitance to change have a significant advantage.
