Mitch - that's a good question that I don't know the answer to (though I'd guess probably not?) Based on Dave's (Sogood51) response, my figure of 2000 hours for a bulb may be low for today's current projectors. I'm going from models I last evaluated maybe 2-3 years ago. Check the manufacturers' specs in any case.
My experience has been that these bulbs DO tend to last their rated lifetime, often much more. I imagine that this would be even more true in a home theater setting, where proper care is the norm (allowing the bulb/projector to cool after powering off and moving, if at all - as opposed to flipping the switch, packing the projector away hot and running off for a flight.)
I haven't seen more than one or two early blowouts in 5+ years of supporting a dozen or so projectors at work as part of our computer services group (that's 60 or so "projector unit years"), and these could easily have been due to the rough use they receive on the road with our sales staff. Like lots of high-end audio tubes, the bulbs seem to last longer than their ratings. Most of them we have in service don't stop working but just get progressively dimmer past their service life.
Even with the cost of the bulbs, there is lots of value to projectors. Here's a quick example: $2000 projector (comes with 1 bulb) + $400 for spare bulb. Bulb life, say 4000 hours each. $2400 / 8000 hours = $0.30 / hour. Super for movies, a little on the high side for TV if you watch alot, but super for special occasions.
