Just my opinion here...
There's a reason Goldberg's is a massive hit, and Schooled is on life support.
I grew up in the 80s and it was totally awesome.
To me, it was the last truly identifiable decade. I can hear a song and place it in the 20's, 30's, 40's, 50's, 60's, 70's, 80's. Same with clothing, hairstyles, and the like. The 80's was the last time SNL and late night talk shows were actually entertaining.
Decades from 90's onward are indistinguishable. Yeah, Nirvana was 90's, but I have a tough time categorizing anything else. Retro has been the thing for the past decade plus, but I can't image a sitcom 20 years from now, set in 2010 for time period laughs. I would absolutely HATE to be a kid growing up in today's world, living under the threat that anything you say or do today will be recorded and used against you in a future time. Such insane pressure to be a good NPC, thinking with the collective. Perhaps this decade has managed to set itself apart, but not in a good way.
But to the Q - if Stranger things was set in a different time period - or in a timeless period, would it still be as big a hit? Great question. For me, the 80's theme sure helped me get into it. It let me connect more with my daughter, who is a big fan. She got to see what life was like for me. So while it helped, I think I'd like it regardless of time period. The casting and characters are compelling, which is half the battle.