It seems like you are just expanding on what I said. Change with social issues bubbles up from the bottom in a numerous amount of ways, but rarely (if ever) comes from the top down. By the time a national party fully embraces changes something it is already politically expedient to do so.
I think we're still a ways apart.
Look, if "change comes from the bottom up" means "national parties react to political pressures, and will only push for a policy when constantly harangued by interest groups within their coalition, and even then only when they're reassured that they won't inadvertently suffer a net loss by pissing off other constituencies," then yeah. That's how it goes.
But if "change comes from the bottom up" means that most advances on social issues come at the state and local levels, and that this is a result of national-level politicians paying "lip service" to issues they don't care about, I gotta disagree. The big wins on racial and gender equality came mostly from the federal level, through courts and legislation. Even on gay rights, the big hope for marriage is a state ballot initiative being struck down by a federal court.
Also, national parties aren't completely separate from state-level activism; it'd be closer to the truth to say they're an aggregate of state-level groups. Congressfolk are drawn largely from governors, mayors, state legislators, county executives, attorney generals, etc. They come up through the same networks, answer to the same constituencies, and in many cases are literally the same people. So it's not like politicians are being genuine when they try to restrict access to abortions on the state level, only to stop caring and start faking once they get to their House seat. They're just dealing with a larger representative body, where neither their party nor the legislature as a whole is going to be nearly as ideologically or culturally homogeneous, so finding majorities is harder.
