I wonder, though, if there couldn't be a happy medium. Imagine a setting that was detailed at the year 1000, as well as the year 1025. The intervening twenty-five years would be described in detail in adventure modules, wargames, novels, etc. But nothing would happen after that point. Nothing published ever - no way, no how. Everything after the self-imposed endpoint would be in the GMs' hands.
It would also allow those GMs who didn't want to be constrained with "what's supposed to happen" to have an incredibly detailed recent history from which to draw when determining the course that his or her campaign is going to follow. Nothing preordained, but a lot of arrows in flight which could land in any one of a dozen places, each impacting the other.
This has a couple of benefits that I can see right off the bat. "Location adventures" such as lost cities, haunted ruins, etc. are somewhat "timeline neutral". The "lost city of Poosh" is just as lost in 1000 as it is in 1025, and one could publish it and have it applicable to either type of GM. "Plot-driven adventures" would, in turn, have a set context for the first type of GM and act as historical background for the second.
If you're one of the gamers that likes the idea of a grand sweeping arc of history, you set your campaign in 1000 and play with all the big events happening in the background, and probably your PCs being involved at one or more crucial events. Your campaign would probably even go off in a different direction, which would be perfectly fine. But you'd have all that other background information to fall back on if you needed it.
Such an arrangement does require a bit of trust between the gamers and the publisher. We've seen examples of such trust being broken in the past (I seem to recall something in the FR Gray Box that said that