My thought
IMO if it were a liberal Zeitgeist, more Democrats would have felt comfortable telling Tipper and other bluenoses to change the channel worry about their own kids vs both Democrats and Repubs feeling the need to accommodate them.
Butterflying away Reagan does a lot to make the anti-liberal religious groups more marginalized.
That doesn't mean nobody else can step up as flag-bearer for the right-wing 1980's backlash against the changes of the 1960's, but without Reagan giving them entree and respectability, they'd have a much more uphill fight.
What does that mean?
Rap, metal, and other music don't have Explicit Lyrics labels on their tapes and albums as advertising of being too naughty for family consumption.
PG-13 doesn't exist, and many 80's movies don't feel the need to be quite so childish to get distributed. The 70's auteur period continues a couple more years or Miramax gets an earlier start.
MTV and VH1 being a cable channel, can be a lot more creative or raunchy with their videos.
AIDS probably gets dealt with as a serious disease in 1982 instead of six years later as a culture war tidbit. Reagan's rhetoric on it was rather harsh.
If dealt with strictly as a public-health issue, it could have infected hundreds of thousands less people and been much easier dealt with.