[TonyTrapp]

There's a variety of reasons:

- Lower-quality components (especially capacitors) being used to meet the lower price point. This is by far the most common failure mode I have experienced, it's never the LEDs dying but the power supply.

- Higher-quality LED light is usually result of driving the LEDs harder, causing them to fail earlier.

- Probably some other reasons too.

[Frenchgeek]

The design may also be completely ignoring heat dissipation, and cook its components.

[tiberious726]

From what I've seen, it's usually skimping on the heatsink over the rectifier.