me too, the family and kid movies has a lot of meanings and are improving every year, and many of them
have messages that are atemporal and even when we were adults still being useful

Films always are a mirror of their times. Really like "he's back again" from T.Vermes as a book for stating that and the film in doing so, too. In there, Hitler stated "well, the people needed Dissipation, and that's why we produced the "Feuerzangenbowle" to get their minds off".
And while Ironman, Deadpool, Batman and what not else is on offer by Marvel and DC surely NEVER had a great plot to begin with, their best times were in times of worry and crisis, as their task was simple: they are the good ones, they turn the tide. With things as Al quaida, IS etc. being there as constant thread, these deus ex machina-films surely don't do much else 8as they also are meant to hit the nerve of the public so that they sell well).

Kids movies on the other hand have to put a lil bit more into consideration: are their characters lovable, indentificational? Does their story have enough speed to keep childrens interest up, yet enough depth to not be dull? And in the end it all should have some educational- or self-finding-experience- value if possible, because kids and education.
As far as these things go, i really like new thought out concepts, because -let's face it- Tangled, cinderella, Snow white and all the other fairy tales surely can only vary so much, already having lost their messages over the ages...

I think you captured a lot here. My question probably could be refined much more as "why don't adult movies get the consideration that children's movies receive?"

Simple entertainment to make loads of money. thus they rely on treaded ways and formula, and on that way the script rarely surprises. At least that is what happens, when you analyse todays movie and tv-landscape: 5 archetypes of stories being respun over and over again.