Regarding rectification: Only some old or cheap HF electronic ballasts for 120V mains had this problem (they were using voltage doubler, what center point was possible to use as lamp current return without anything). Most new ballasts use bridge rectifier with PFC to boost the DC voltage to required ~300..400V, so no such "handy" node is in the circuit, so it is not possible to avoid the use of capacitor DC decoupling.
Low frequency HID ballast operate lamps at quasi-DC (DC with periodically reversed polarity - current is bipolar square wave), where they don't care about DC voltage component - depend on design they or deliver constant current (regulated by slow regulation loop to maintain constant average power) or directly constant power, so unlike with magnetic ballasts there is no excessive current as result of rectification.
I think the disappearing HID magnetic ballasts are some error - it does not make sense to do electronic for >250W, as the efficiency of both is about the same from 150W and above.
But i think it has more to do with expected elimination of quartz MH's in EU (due to efficacy requirement limits), while ceramic are max 250W and for 250W electronic are available.
I think those "outdoor" rated (-40..80degC) would have not big isues - when i saw problems, it was somebody "saving money" by using cheaper indoor (0..70degC) rated ballast outdoors, so exceeded at least it's temperature rating.