It's phenomenally complicated question. Jaw is both a magnificent story and technically brilliant. Then you get something that is absolute drivel like the color purple.
If you look at his
IMDB The breath of output is staggering. I mean as a producer he gave us both Seaquest DSV and Pinky and Brain. It's impossible to be consistently good with massive body of work he's putting out is just impossible.
Also I think you're putting too much faith in auteur theory. Lets take between 2001 and 2005 shall we?
He directed.
# Munich (2005)
... aka Steven Spielberg's Munich (Australia)
# War of the Worlds (2005)
# The Terminal (2004)
# Catch Me If You Can (2002)
# Minority Report (2002)
# Artificial Intelligence: AI (2001)
He produced.
# Munich (2005) (producer)
... aka Steven Spielberg's Munich (Australia)
# Memoirs of a Geisha (2005) (producer)
# The Legend of Zorro (2005) (executive producer)
... aka Z (USA: poster title)
# "Into the West" (2005) TV mini-series (executive producer) (unknown episodes)
# Dan Finnerty & the Dan Band: I Am Woman (2005) (TV) (executive producer)
# The Terminal (2004) (producer)
# Voices from the List (2004) (V) (executive producer)
# Burma Bridge Busters (2003) (TV) (executive producer)
# Catch Me If You Can (2002) (producer)
# "Taken" (2002) TV series (executive producer) (unknown episodes)
... aka Steven Spielberg Presents Taken (USA: complete title)
# Men in Black II (2002) (executive producer)
... aka MIB 2 (USA: promotional abbreviation)
... aka MIIB (USA: promotional abbreviation)
# Price for Peace (2002) (executive producer)
# "Broken Silence" (2002) TV mini-series (executive producer)
# We Stand Alone Together (2001) (TV) (executive producer)
... aka We Stand Alone Together: The Men of Easy Company (Europe: English title: DVD title)
# "Band of Brothers" (2001) TV mini-series (executive producer) (unknown episodes)
# Jurassic Park III (2001) (executive producer)
... aka JP3 (USA: promotional abbreviation)
# Artificial Intelligence: AI (2001) (producer)
... aka A.I. Artificial Intelligence (USA: poster title)
# Evolution (2001) (executive producer) (uncredited)
# Shrek (2001) (executive producer) (uncredited)
# Semper Fi (2001) (TV) (executive producer)
and he wrote
# Medal of Honor: Pacific Assault (2004) (VG) (creator)
# Medal of Honor: Rising Sun (2003) (VG) (creator)
# Medal of Honor: Allied Assault - Spearhead (2003) (VG) (creator)
# Medal of Honor: Frontline (2002) (VG) (creator)
# Medal of Honor: Allied Assault (2002) (VG) (creator)
# Artificial Intelligence: AI (2001) (screenplay)
... aka A.I. Artificial Intelligence (USA: poster title)
# Medal of Honor: Underground (2000) (VG) (creator)
And
six of those are video games
Do you really think every one of those projects could get his complete undivided attention? Christ he even fitted in;
Star Wars: Episode III - Revenge of the Sith (2005)
(assistant director: action scenes)
If you think he managed to do all that, and give the 6 films he directed in that period in his complete undivided attention you're deluded. He's a producer and director who surrounds himself with the best technicians and artists in the world. Janusz Kaminski shoots all his films. Michael Kahn cuts all his films. Joanna Johnston has been in charge of wardrobe for decades. John Williams always does his score.
Get the picture yet, at the level Spielberg works at, there's nothing auteur about it, there's a full team he always uses. So whenever you see a Spielberg movie, you know you're going to watch as technically perfect a film as you can see. It then lives and dies on the plot. Take saving private ryan, phenomenal opening act, solid second act, let down by an ending that is pure smaltz John Wayne esque bollocks.