To assume a manufacturer builds for duration would be a faulty assumption. But, the first LED bulb I bought is 4.5 years in running constantly and coming up on 40,000 hours.
Now, I have a couple of LED bulbs that have been continuously operating in outside sconces since November 2014 (~20K hours) without a flicker and those are house brand from Lowes. Not a single flicker and have survived through winter cold and summer heat and humidity.