I say this with love, kindnesss, and respect:
if the OP were talking about, say, toddlers, and said: the kids want to take a mid-day nap every day -- they actually want to go all the way back to the hotel, SLEEP for two or three hours, then go back to the parks only to return to the hotel in time for dinner -- they will ruin our vacation and miss out on all the fun! -- then everyone would try to find a kind way to respond to say, well you know, the little ones really do need their sleep and will probably be less cranky and more inclined to enjoy themselves if you did find a way to work in their naps for them....
Again, please -- I mean only good things here -- developmentally, physiologically, teens NEED sleep (and need more sleep than toddlers do) because of the HUGE changes their bodies are going through. Believe me, I understand the temptation to see teen sleepiness as laziness (they give us enough other indications of that sometimes, to be sure

); but the scientific, medical fact is that teens do need LOTS of sleep for their brains and bodies to develop and cope with their growth. Honest. Additionally, the changes that they are going through developmentally really DO make late mornings and late evenings make sense for them -- that cycle really does work from a physiological perspective for them.
LONG way of saying that a compromise that does allow for some of the sleep teens need really will make a better vacation for them which could go a long way towards making a better vacation for you
