I have the exact opposite experience, virtually every single light bulb I have torn down - one LED (all in series) has a black dot, if I shorten it - it will 'work' again. The bulbs I have seen tend to drive the LEDs so hard that some of the latter fail, power supplies might have huge ripple but generally don't fail catastrophically.

Edit: now thinking, it can be a US thing, with the voltage being ~120. Lower AC voltages means worse efficiency for the power supply (and all of them tend to be universal, unless totally cheapen out on the primary capacitor [250V] for the US market). Generally speaking low AC voltages have mostly disadvantages.