One of my big-screens is a somewhat older “rear-projection” model — it has a single bright white light, that is used to drive the display. It fades over time, and will last maybe 15,000 hours. It is however replaceable — costs around $200 bucks, but cheaper I think if I shop around.
I’ve bought 3 replacements, so I always have one around, and I’m on my 3rd bulb, so I still have one left. I’d say it lasts about 2 years per bulb, so in another year I’ll probably buy another replacement bulb, and then ditch the TV when I run out because there is better technology coming.
Insted of just ditching it, sell it on eBay. I’ve done that successfully with two rear projection CRT TVs.