Arnold was a millionaire from real estate before the movies, so he was successful anyway
No he wasn't. That's all BS.
He got a small stipend from Joe Weider and made only a small amounts from his Olympia wins. The purses were very small. As far as the bricklayer nonsense and real estate investments, where would he have gotten the money to invest? Selling bodybuilding mail order courses? Some money but not a lot. He didn't make any serious money in those years.
He didn't start cashing in until 1984 with Conan the Destroyer (Conan 2) and Terminator.
His career movie earnings are well over $200 million.
https://www.imdb.com/name/nm0000216/bio?ref_=nm_ov_bio_sm#salarySalary:
Hercules in New York (1970) $12,000
Conan the Barbarian (1982) $250,000
Conan the Destroyer (1984) $1,000,000
The Terminator (1984) $750,000
Commando (1985) $1,500,000
Predator (1987) $3,000,000
The Running Man (1987) $5,000,000
Red Heat (1988) $8,000,000
Total Recall (1990) $10,000,000
Kindergarten Cop (1990) $12,000,000
Terminator 2: Judgment Day (1991) $15,000,000
Last Action Hero (1993) $15,000,000
True Lies (1994) $15,000,000
Junior (1994) $15,000,000
Eraser (1996) $20,000,000
Jingle All the Way (1996) $20,000,000
Batman & Robin (1997) $25,000,000
End of Days (1999) $22,000,000
The 6th Day (2000) $25,000,000
Collateral Damage (2002) $25,000,000
Terminator 3: Rise of the Machines (2003) $29,250,000
The Last Stand (2013) $5,000,000 +25% of first dollar