One now mocks the concepts and conceits he built his reputation on, while the other seems to now be embracing concepts and stories that he once considered goofy. 

Time between DARK KNIGHT RETURNS and ALL-STAR BATMAN...21 years.

Time between NEW X-MEN and ALL-STAR SUPERMAN...2 years.

"Deconstruction" of superheroes: Morrison (28 year career)...DOOM PATROL, ANIMAL MAN, KID ETERNITY, MARVEL BOY, FANTASTIC FOUR 1234, SEVEN SOLDIERS OF VICTORY

Miller (28 year career): None.

"Straight" superhero work (career): Morrison...JLA, X-MEN, BATMAN, ALL-STAR SUPERMAN

Miller: DAREDEVIL, WOLVERINE, DARK KNIGHT RETURNS, BATMAN YEAR ONE, BIG GUY AND RUSTY THE BOY ROBOT

Major notable contribution to comics outside of superhero stories (career): Morrison...none.

Miller: SIN CITY, 300.

Results: Grant Morrison...bored with "B-list" characters? free rein, and "decontruction" occurs. Political/satirical slant more extreme on these books. Editorial reins tighter on major characters. "Straight" treatment...edict from the editors, or Morrison respecting characters? Unknown.

Frank Miller...B-list character turned into A-list character by treating "straight", adding art influences and filmic story-telling techniques to create a "style" all his own. Major character Batman, respectfully redefined, initiating an entire sub-genre of "hard-boiled" superhero fiction...Miller's SIN CITY culminates a lifetime of film, novel, and comic book knowledge.

Heh heh... just like when a little boy gets upset when someone refers to his action figures as dolls.  "They're not dolls, they are action figures!  They're not superheroes, they're metahumans!"

Dude, you gotta have Sasquatch on the drums.

Who plays bass?

Galactus maybe?

I had a kind of "Okay, that works…" reaction when I first heard the term "action figure". The irony, tho, was that the phrase first started appearing around the same time that those toys were turning into "collectibles", and never likely to see much "action".