I'm not sure Thunderball if it was released today if it would make that much money.
In terms of spectacle, scope, and special effects,
Thunderball was one of the biggest movies of its day. That's why it was so successful. The James Bond franchise, in general, is a "standard" action movie series. But Thunderball wasn't quite that. It had groundbreaking, and Academy Award Winning, effects sequences. The underwater battle scene, for today's standards, is slow and boring. But at the time, it blew people away.
Look at the 5 most successful Bond movies. Three of them are
Thunderball,
You Only Live Twice, and
Moonraker. What do these three films have in common? They're effects-heavy, cartoonish, and over-the-top. It's the elephant in the room that Bond fans don't like to acknowledge. Audiences love it when Bond is more fantastical.
Goldfinger and
Skyfall seem to be the exception. Although...
Goldfinger was pretty out-there as well.
back in Connery's early days there was no such thing as a dvd or vhs, so if you wanted to see a movie you had better catch it on the big screen.
Dr. No - 18.9 million
FRWL - 26.6 million
Goldfinger - 66.3 million
Thunderball - 74.8 million
YOLT - 35.9 million
DAF - 26.5 million
NSNA - 17.5 million
The ticket sales (and box office adjusted gross) for
Goldfinger and
Thunderball are WAY higher than the rest of the Connery films. As well as the rest of the James Bond series. Those are the two gorillas in the franchise and they always will be. Sean Connery will always benefit because he starred in the two mega-hits the franchise had.