I don't understand why the LED lights are failing - vibration should be less of a problem with them than with a filament bulb.
Perhaps cheap one are only specced to just 12V, so the ~14V charging on a bike cooks them off in the first few months.
Its very frustrating, but even the 'posh' bikevis ones have failed on me once, and the others are slowly turning blue (from white!) which was noticed on ST3. Someone has said its the electronic components involved which are failing due to vibes, not the actual light-emission diode itself if that makes sense?
My bikevis ones are mounted outside the lamp, away from significant heat, Juv...I don't seem to be having other issues with lighting or electricals at all (though I haven't tested voltage output).
Royzx and james.t - can you recall what exact led's you got that keep working?