Appropriate (in my book) is what works for each individual family.
<Grinning> Heck, in the winter my 8 yo goes to bed by 6pm (we're up in the morning at 5am to be on the mountain, and home again at 5pm, which leaves us an hour). But in Rome he doesn't go to bed until apx 1am (it's cultural to take a nap in the afternoon and have dinner at 10-11pm). But most of the year he's in bed at 9pm. Although (since we homeschool) I have no compunction whatsoever of putting him to bed at 3pm so that we can watch a meteorshower from 2am-5am, OR to keep him out an about at the theatre/ballet/opera/rock concert until midnight and let him sleep until "lunchtime" several times a month.
The thing is MOST people get locked into a school bell schedule for 13-16 years (depending on whether or not they do preschool)... and as such have to arrange bedtime in order to suit school bells. Which creates a homoginizing 8ish bedtime for most American children. Also, since most kids have sibs... it just makes sense to get and keep younger ones on the same schedule as their older ones. So 8PM is almost written in stone in the American Psyche ((I KNOW it was in mine, I 2nd guessed myself for YEARS... because no matter how much sense it made in our own family... it just felt "weird" because it was outside of the norm.)) Outside of the norm isn't automatically wrong.
:) It's also what people pick up on conversationally. Outside of the norm catches our attention, so we say something... for myself, it's because I'm interested in how and why other's do things. For others it runs the gamut of reasons... from curiosity, to judgement, to defensiveness/fear, to "making conversation", to idea generating... ALL kinds of reasons. Most people I've met, however, seem to be genuinely curious as to why we do things differently, and how it "works" or "challenges" associated with it. LOL the people who (In my experience) actually jump straight to judgement are, rather ironically, those I'm closest to. Sometimes the judge in my favor (I could say I'm painting kiddo blue... and they would respond "Of COURSE you are! What other color makes sense?" (love them dearly, because they only care for my happiness... but there's no critical analysis... which confuses me, I like to understand something before I support it, no matter WHO is presenting it)... to those who "tell me how it is" (aka what I'm screwing up, how, and what I "should" be doing -I always insert "If you know what's good for you" with a movie-mafia accent. Oy. Also, the idea anyone has the "right" to tell me I'm an idiot with no critical analysis also irks me)
But yeah... "Best" is always different with each and every family and their own unique situation.
If it works for you, revel in it. And keep it :)