That’s not quite true. He had written and directed Repulsion, a British film starring Catherine Deneauve that was still a huge hit in the U.S. in 1965. He was being lauded as the new Alfred Hitchcock and was definitely considered a wunderkind in a time period when “auteur” directors were considerable celebrities, and he certainly milked that. “Rosemary’s Baby” for that matter had been a major, major hit. So Polanski was definitely an established name.
To put it another way, Polanski was certainly rich & famous enough to have a huge spread in Beverly Hills and the murder of his starlet wife became international news long before anybody outside “the Family” knew the name Charles Manson. (He wasn’t even a serious suspect until almost a year after the murders took place.)
That said, Sharon Tate while was probably more notable at the time for being Polanski’s wife, but she was still at the beginning of her career. She was definitely part of the Hollywood A-list crowd and likely would have had a more successful career if she’d lived, including possilbly appearing in her husband’s films.
As for whether Polanski would have done what he did…I would think it likely. What happened to Tate was a huge tragedy, but he still seemed like a sleazy guy (though talented film-maker) from the get-go.
Repulsion is really an art house film. It was a $300k b&w film. RB was a $2,300k color film. It didn’t really make a ripple in regard to the average movie goer. (And it is hella creepy.) It attracted a lot of critical attention, but that mattered little in the pre-Rotten Tomatoes days. RB made over $33m. No one seems to have any data on Repulsion, which is telling.
10050 Cielo Drive was hardly a huge spread. 3 acres. Bought for $710k (inflation adjusted) in the early 60s. Rented out to people like Polanski. And renting isn’t as big an outlay as buying.
The murders took place on Aug 8-9, 1969. The big break came in mid October. By December 1st, most of the family had been arrested. The trial started started June 15. How is this “almost a year after”?