To me 3500K is about where it's at for LED's. Everything in a higher spectrum is just noise to me. Strangely I have found some 5000K LED's that I have liked the output of. Not sure why. To each their own.
Yes, but you seem to be talking more about aesthetic preference, as opposed to what enables your vision to function optimally. Plenty of people, for example, still prefer to light their homes with 2700K or 3000K, even those choices are awful for actually seeing well. By well I mean with good contrast. Even those people might opt for 5000K for task lighting where the ability to see is more important than aesthetics. Since headlights and streetlights are solely for task lighting, it makes sense to go with what produces optimal results, and that's pretty much in the 4000K to 5000K range.
The 5000K LEDs you liked the output of may well have been high CRI. Even when talking aesthetic preferences, CRI often matters. For example, I hear about people preferring lower CCT lights because they show reds and yellows better. But that's only true if you're comparing CRI 70 or 80 lights. CRI 95 LEDs, even 5000K ones, bring out warmer colors nicely, plus their overall color balance resembles sunlight. At this point I tend to stick solely with CRI 90 or better. No good reason not to given that they're readily available, and only a little less efficient than CRI 80.
Another weird factoid I've noticed is that you can make do with lower illumination levels in terms of lux, but have the same apparent brightness, with higher CRI LEDs. So that sort of compensates for their slightly lower efficiency.