The Vulcans have landed in Star Trek: Picard's 20th century timeline, and the reason for their presence is explained by Star Trek: Enterprise. When Patrick Stewart's Jean-Luc Picard found himself nabbed by the FBI at Guinan's bar, he perhaps didn't expect to be conducting an impromptu therapy session, but that's exactly what transpires in Star Trek: Picard season 2's "Mercy." As a young child, the FBI's Agent Martin Wells (played by Star Trek: Voyager's Jay Karnes, incidentally) experienced a terrifying forest encounter with a Vulcan, mistaking a Mind-Meld for some kind of mental assault. Agent Wells has wanted to believe ever since...
Assuming Wells is roughly the age of his actor, the future FBI Agent's random alien meeting would've taken place somewhere around 1980. This should be a year of Pac-Man and Dallas, not pointy-eared aliens lurking in a forest. Moreover, Star Trek: First Contact established the first official meeting between Earthling and Vulcan occurs in 2063 - almost a century before Agent Wells' flashback in Star Trek: Picard. What in the name of all that's logical are Vulcans doing on Earth so early?
An answer can be found in Star Trek: Enterprise - specifically season 2's "Carbon Creek." In this episode, the NX-01 Enterprise's Vulcan science officer, T'Pol, reveals her grandmother was sent to survey Earth following the launch of Sputnik 1 - the planet's very first satellite - in 1957. The Vulcan team crashed on Earth, and spent a few months living among the humans in secret, making full use of long hairstyles and beanie hats. One of these Vulcans - a male named Mestral - even stayed behind after T'Pol's grandmother and the others were rescued. From the flashback in Star Trek: Picard season 2's "Mercy," we can assume Vulcan maintained a clandestine, peaceful presence on Earth from 1957 all the way through to First Contact Day.
Maybe another Vulcan survey team crash-landed in the 1970s/1980s. Or perhaps the "Carbon Creek" incident showed Vulcan it could get away with sending scientists onto Earth's surface without being detected, so made full use of humanity's uncanny ability to ignore what it doesn't wish to see. The pair Agent Wells meet certainly appear to be studying something, after all. The two Vulcans from Star Trek: Picard might even be connected to Mestral in some way - thought not officially, since his decision to remain on Earth was covered up by T'Pol's grandmother and the others. Whatever the mystery Vulcans are up to, Star Trek: Enterprise provides the context behind Wells' shock alien encounter - Vulcans were interested in humanity as soon as we began looking toward space, and although every effort was made to avoid traumatizing young children, they weren't always successful.
Just like Christmas, the true spirit of First Contact Day seems to diminish every year. What was once thought to be Earth's bold first step toward space exploration is actually just the date Vulcan decided to let us in on the joke. After Star Trek: Enterprise, Star Trek: Picard continues to prove Spock's pointy-eared ancestors were here long before First Contact Day.
Star Trek: Picard continues Thursdays on Paramount+.