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?”
Yeah. It would trigger a shit storm in 10 years time we wouldn’t spend all day every day talking about the day we found out aliens existed, we would be talking about the ongoing wars arising as a result of their tech or some other thing.