Fact is, the automotive headlights are driving the LEDs way harder than it is common with general lighting. Paertially because auto headlights needprecise beam control which needs high intensity packaged to a small area, partly because car headlights use to be designed by far shorter lifetime than general lighting, because simply the cars do not run that many hours over their runtime. Normal passenger car lifetime of 300000km/200000mi means about 5k hours running, headlights are on for barely 1/3 of that, so lifetime of 2k hours means the headlight will last the whole car life, which means less than 1/10 of typical lifetime requirement vs general lighting. And the headlights are really engineered to last just that, to get the required performance at the lowest cost possible, so some degradation effects may already show up, mainly when they do not constitute headlight failure.
And the hard drive may mean different degradation effects than usual for general lighting become dominant. And then there is many years of off state parking time, when the humidity may corrode things without being drawn out by the heat of normal operation.