A single family home built to today's standards will be safer than an apartment built 50 years ago. Of course newer built anything complying with modernized fire safety regulations will be safer than older anything. I feel like your point is missing the mark
A major contributor to this statistic is fire sprinklers. New apartment complex construction for decades has required them but they're virtually nonexistent in single-family homes, and that's unlikely to change anytime soon.
California has mandated it for new construction for over a decade now. Of course old stock doesn't really ever turn over in California so it's entirely possible that we will never reach a point where a majority of SFH in California have sprinklers, but it's certainly possible to change for new homes.