At the very least, unless hardware/processing inhibits, firmware and feature updates should cover two generations of hardware. If the X100s can support X100t updates, why the hell not? Did I not invest in a rock-solid, long-lasting piece of gear at a premium for a reason?
Would be much more of a motivator for me to stay with the Fuji family, since I upgrade gear every other generation.
Of course, I joined the family with the X100s and am a bit pissy at the moment...