People who would, instead of eg living in SF, have lived in Oakland, SSF, San Mateo etc instead move to SF and nothing changes and/or net increased rent results

People who would, instead of eg living in SF, have lived in Oakland, SSF, San Mateo etc instead move to SF and nothing changes and/or net increased rent results? Continuing to allow the peninsula to add jobs and dump its housing problem on SF obviously doesn't help priced out SF residents. And in SF, at least some of those higher end housing projects remove housing first. Nothing in economics says it's obvious without observation or experiment that adding expensive housing in SF helps affordability for lower income brackets.