Oh I see you point.I think it was more that because there was an unknown actor playing Bond, they hired a well-known actress for the female lead (Rigg having been in the Avengers). Had Connery been in the lead, they would probably have been content to get a less famous - and cheaper - actress to co-star.
But didn’t goldfinger use honor Blackman who - ironically - was replaced on the avengers by rigg? From what I read, the biggest issue with the avengers were they grossly underpaid their female leads.
Sir Sean in OHMSS would have been interesting. Maybe being challenged to do more than one emotion as Bond would have brought out his acting chops and playing against Rigg would have lifted up his performance.