Manson was from West Virginia. IMO he was a dupe for the Hollywood drug scene. The murders were ‘for hire’ retaliation for dopoe deals turned bad which were covered up!
FBI pioneering profiler John Douglas said he didn’t think Manson intended for anyone to be killed.
I have read a few books on Manson, never heard that theory before. I can see how the Tate murders could fit in, but not the LaBianca's. They were a pretty normal couple, as I recall.
I thought Cielo Drive was the former home of Terry Melcher, sometime producer for (and sometime member of) the Beach Boys.
Melcher thought Manson was not that great, and didn't want to work with him. We don't know what language Melcher used to communicate his lack of interest to Manson, but (knowing the LA music scene a little) he might have been fairly brutal in giving his verdict. There might have been a dope deal involved also, I think Manson was selling drugs to get by at the time, but I'm not sure.
By the time Manson's people turned up to murder everyone, Melcher had moved elsewhere; Roman Polanski was just one of a series of renters.