Because HS is now the only actual 'brewery membership' thing; you know, the single tier that all other brewery membership's are like. It just happens to cost a lot, as with most California crap.
RS is now the proving grounds, a test to see if you are worthy willing to shell out obscene cash for the janky **** first before you might make HS. It's also where more and more experimental failures are relegated to because **** RS people - anyone can just sign up so it's not exclusive enough.
PS (Preservation for those who have forgotten this still existed) is for morons who want to half-ass an RS membership, but with less committment. It's a joke, to lull rubes into thinking they're saving money by skipping quarters that don't interest them but they will be third-class citizens in any event. Plus, Patrick Rue gets to earn some spare change on the side for parking meters and such.