Perhaps fast track product that released on the population in the past 5 years?

It's not that, although COVID has something to do with it. Under lockdowns, most people were told not to go outside, so we stayed put. Meanwhile, the Zetans were finally free to take the skies, and improve their cloaking technology without billions of people seeing them zoom across the stars. Now it's good enough that they can hover a few feet above you, spreading their rays. That's the cause of the memory and thinking issues.