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?”
I think 80% of the world would look up, go “huh. Well, anyway…”
The remaining 20% would be split at either side of the spectrum, with 10% on one side freaking out and trying to whip the 80% into a frenzy, while the last 10% would be a mix of, “PLEASE TAKE ME WITH YOU DON’T LEAVE ME HERE PLEASE”, “HnnnnnnNNNGGG IM COOOOOOMING”, and “Why do we all have to wear these ridiculous ties?”