[convolvatron]

I totally agree that if run them cool enough they last forever.

but I had some bridgelux 10W that I just threw in some copper tubes on an aluminum slug with a minor affordance for cooling (some slots cut in the Al to promote convection). These ran at 80C and lasted for >5 yr at at least 80% brightness. and still the primary failure mode was the little meanwell dc/dc converters playing thermal runaway. and that whole assembly cost $10

it just has to be penny pinching at the end of the day.