Was it a movie? Was it a shift in society change? Was it his age?
Did somebody or something poke the balloon and suggest 'Hey, this guy really isn't a movie star anymore time to move on'.
I've seen this with other careers of once SUPER HOT movie stars:
Robin Williams
Jim Carrey
Tom Hanks
Harrison Ford
...something pokes the balloon and the air lets out. And suddenly you go from being hot/cool to cold/failure.
By the Erasor and his following films they stopped making movies that fit his style. Gone were the bombastic 80s action movies with kill counts and quips after every death.
Hollywood changed, action movies changed and he kept getting thrown dud scripts that didn't play to his strengths.
Personally, I think that taking time off to be the Governor of California started it. Out of the movie audience vision.
I believe that what continued the fall was his infidelity when he was Governor.
A lot of people (me and my wife included) lost a lot of respect for him.
I think Arnold eventually became a caricature of himself. He was never much of an actor, and that thick accent (along with his musculature) sort of pigeonholed and typecast him into a specific category. He cashed in on that for a long time, and was good in those kinds of roles. Plus, he was likeable and had good screen presence.
However, as he aged and no longer stood out as having a superhuman physique, he started to lose his draw. Combine this with questionable role selections (his "Last Action Hero" was like Stallone's "Throw Momma from the Train"). Mix in the fact that he had some bad press (for his extra-marital affair)....he took time off to enter politics....and the action movie genre he was used to had begun to shift and "evolve", and that explains why he lost his mojo.
The really odd wildcard in all of this is that THICK accent, which never diluted over time. That contributed to the fact that, whenever you saw Arnold on-screen...you saw the iconic action star, and not the character he was playing. At least Stallone could fall back to his franchises. But Arnie couldn't slip into character roles or drama. Action movies were his thing...and few few actors can carry that kind of career into their older years without also having some great acting chops (and fortunate genes), like Ford, Connery, Neeson, and to a certain degree, Mel.
Of all the top action guys of the 80's, Stallone was the only one who was really an actor, per-se, unless you widen the scope to include Mel Gibson and Bruce Willis (Bruce started late in the decade and Mel was more a dramatic actor who did occasional action parts, but not as some sort of superhuman killing machine). Stallone had very limited range but was a trained writer and actor so could act dramatic circles around the likes of Schwarzenegger, Van Damme, Norris, and Seagal. The fact that he got all buffed up into a brawny superhero was secondary to his acting ability.
shareIt didn't help that he slept with someone that wasn't his wife and had a love child with her, and kept it hidden for years, or that he made the mistake of trying to be governor of California, a state notorious for having the entire state govt. full of corrupt fools that only care about themselves.
shareEntering politics aged him. His movies afterward were no longer cool.
shareI wish he’d just stayed retired from acting after T3. Terminator Genesys really tarnished his legacy.
share"What broke his MOJO?"
He had too many freedoms.