"Retro" ALWAYS does well. The problem with retro is that it runs through the same cycle as everything else. In about 5 years, the 90s/grunge-era is going to be the new hotness (look at fashion - which tends to drive it - and you'll see it coming). "Retro" exists because creators use their childhoods for inspiration. Stranger Things takes place in the 80s because the Duffers grew up in/influenced by the 80s. Future creators will use their appropriate decades.
HHN did well because of Stranger Things. No one said, "Oh, look, VHS. We should go this year." There was no "80s theme;" just a limited 80s aesthetic that had no impact on the event overall. Because none of the actual marketing (billboards/commercials) carried that aesthetic. It was a popular IP.
The NES console initially sold out because Nintendo intentionally limits quantities. Once they re-released it, it sold out much less frequently. Both were popular because they were the only way for a wide swath of gamers to access all-time classic games (Zeldas, Marios, Earthbound). It wasn't because it was retro. They could have released the same games in a Coke can and it would have sold well.
The issue with retro properties in entertainment, however, is they age out exponentially. They're not "new" properties. Once the initial "oh, this is fun" wears off, you're left with 30 year old property instead of a three year old property. That's actually why MOST rebooted/revived stuff from the 80s/90s is either widely different or a miserable failure.
People like to tout Stranger Things as a "retro success." But it's not. It's a new property, telling a story that could work in any time period. Putting it in the 80s is the hook.