Dynamos certainly do require power to create power. 6-8 watts worth to power the headlamp at around 25-30kph and this figure is for the very best dynamos. Unless you have created the perpetual motion machine?

I have been on many climbs recently with the dyno bikes and the lights flicker. Are you saying their shiny dynamos are 35 years old? I doubt it. The flicker on a steep climb is annoying. If there is dynamo that will not flicker on a 30 minute climb at a 4 mph pace, please let me know and I will stand corrected.

Do a little research, there have been plenty of head lamp water infiltration issues and yes, some high priced German lamps have a cute little hole positioned perfectly to let water inside.

As I indicated, I can do an all night summer ride on one set of batteries with better (in my opinion) light output than a dynamo power headlamp. I always have batteries charged.

Both battery and dynamo power sources have their place depending upon a rider's needs and budget. A dynamo makes no sense for my use. I want to be able to take the entire lighting apparatus off the bike and put it on only when needed and to do so quickly. I want to be able to swap from one bike to the next. I am also unwilling to lose 1 kph from the generator drag. My two battery setups that I use on a long ride weighs about the same or less than a complete dynamo setup and has significantly higher reliability due to redundancy alone even if we ignore the waterproof issues on some dynamo headlamps. For my needs, there is absolutely nothing you can say to convince me a dynamo makes sense. I have analysed this from every angle....from my requirements that admittably are not the same as yours......