Seriously, I doubt it would even take that long. We get used to shit so quickly, and the news cycles have to keep feeding us new things, the only way we’d keep talking about the aliens if they kept doing new and interesting things. I’d be willing to bet a year later there would be some people who straight up forgot about it. “Oh yeah, aliens! Are they gonna, like, visit at some point or just keep exchanging calls with the Whitehouse?”
Oh, wow, you’re totally gonna love Star Trek when you finally see all 58 years of the shows and films. Then there’s Dr. Who and Star Wars…
Sci-fi has been a very profitable field for at least 60 years. Arguably over 150.