I have had experience with 4 different 3 lcd projectors.
My friends PTAE200u (480p): Still kicking along just fine. 480p low lumens low contrast but works.
My original PTAE900u (decent 720p for it's time): It was hurt by 3 thousand hours (white was not white, large odd color variations) Dead at 2000 or so on the 2nd bulb, 6000k hours or so total. Vertical line death.
My friends Sanyo 1080p. The on the under 2k 1080p ones. He is living with some Image quality issues and probaly has less than a 1000 hours on it.
My Epson 6100 (basic 1080p) Bought used with 600 hours. By 1800 hours it has a small blue tint on the bottom on the screen that gets better as it warms but the rest of the PJ looks sharp.
Likely there were all the "lesser" panels.
I know others have had different experiences but I consider projectors to be disposable. I used 1000-2000 hours a year on the PJ. LED / Laser may cause me to pop for new tech again (I don't care about 3d) if something comes out that would work in my rear shelf mount theatre. 3 year year warranty my also be in my future I will make the decestion when the Epson dies or needs its next bulb.
Also you know your PJ bulb dims over time?
4000-10000 hours sounds pretty spot on from my experiences. Remember you have a couple hundred watt bulb in a small box with lead free solder.