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?”
My friend and I came to this conclusion like 20 years ago. Once the shock wears off everyone’s minds will adapt, with most people falling into “great, there’s aliens, but I’ve still got to get to work.” I mean the US only sorta screeched to a halt for like a week after 9/11, and most of that was the airline industry. The pandemic was way worse, but the problem was very different. So unless the aliens do something (good or bad) that affected everyone directly - war, disease, super powers, apotheosis, free global WiFi, w/e - we’d all be back up and running in like 4 hours.