Fitting brighter headlines would be mostly a one-off spend, with only small ongoing costs for periodic replacement of lamps and specifying them for new fleets. However, the safety benefit continues to apply indefinitely, or at least until LU gets platform screen doors on all stations which is probably the same thing. So the brighter headlights are worthwhile even if they only save one life ever.
Any such fitment would however have to consider other hazards such as dazzling drivers of trains in the other direction.
The headlight brightness thing is a bit of a red herring - particularly in this case, where the S Stock does have very bright LED headlights.
I'm scanning the platform train interface (PTI) when coming into platforms - is anyone beyond the yellow line, are there kids running around, is anyone cycling, fighting, are there any other risks, such as damaged infrastructure, unattended luggage, and on and on and on.
I know it sounds counterintuitive, but the "track" is a supposedly inherently safe space, so very little of my attention is spent scanning the rails as
nobody is supposed to be there.
A secondary consideration is that trains don't stop on a dime, so even if I do see a person, there is little chance of stopping at the speeds I enter platforms. I gauge my braking for maximum efficiency to bring the train to a stop at the stopping point at the headwall, not half way along the platform. There may be an argument to say 'enter the platforms slower' but this would obviously have an impact on the service and require a timetable revision.
Lastly, Ickenham has recently had the platform lighting upgraded - they are now very bright LEDs. I don't know if this is a result of the incident last year, or part of LU’s commitment to convert all LU property to LED.