Here's the thing about these 2 points you made.
This proves the importance of social media at least from a standpoint of understand what is culturally important to people of all demographics.
Yeah...if YOU understand it you better believe THEY understand it...the conditioning doesn't stop just because you're on "your" facebook, like I said, reality TV is scripted, the media is still the "media" even when you put social in front of it.
I don't think black folk just up and stopped caring about the other aspects of the culture, they just aren't exposed to it because "Hip Hop is a genre". You can't buy a mural or a dance move, a beat box ect.
Based on my social media followers and the people I follow I can give you somewhat of an idea of what is still seen as relevant to black people.
From an entertainment and more serious means of relevancy.
From as serious as police brutality to as meaningless as what songs are popular. Social media has kept me updated on what people care about.
While I have seen people post battle rap I've never seen anyone post anything pertaining to hip-hop culture outside of that and rap music.
That's what's leading me to believe the "culture" of hip-hop has and continues to decline
You should probably use a little more discernment in life, generally.