There was a proposed SW novel, never finished and now held non-cannon, that intended to link Lucas' first film THX-1138 with the Star Wars universe as an explanation for how humans got to the SW galaxy. In it THX and about 500 other humans from the 25th century escape Earth in a rocket ship. The ship falls through a wormhole in BOTH TIME AND SPACE that drops them in the distant SW galaxy many thousands of years ago, either before or at the beginning of the Infinite Empire. It establishes a genealogy of sorts for the origin of some family names like Skywalker and why some historians believe Corusant may be the UNKNOWN original homeworld of humanity. You can research it all up on the SW wookiepedia site.
What we do get from this is that there is no official SW explanation of where humans came from and that the distances between major galaxies is too far for even hyperdrive engines to traverse. If the E.T. easter egg appearance is taken seriously as the same race as in the film E.T., then we'd have to assume that this exploration craft of theirs fell through the same wormhole which is bridging 1980s on our end to whenever they launched (20 ABY?) on the SW end.
This still would allow for millions of years difference between star wars time and our time since all that is defined in canon is that the star wars saga occurs a long long time ago and in another galaxy far far away. This is why every date in star wars is measured from either before or after the Battle of Yavin because its the only touchstone we have for the saga.
Even if SW occurred in the Andromeda galaxy, our nearest neighbor, it would be 2,538,000 light years away. So a hyperdrive ship used to refueling after a few weeks of flight at less than 130,000 LY (diameter of the galaxy) wouldn't make it to there and back without a lot of tweaking. Nobody is going to be willing to take a near lightspeed journey for 2.5 million years. Even if ship time was dilated to near zero there would be no point in returning. Either E.T. has escaped the SW galaxy in a multi-million year colony ship, is an unrelated species and just happens to look the same, or found a lost wormhole between the SW and our galaxies that possibly could explain how humans got from one to the other in the past. If E.T. gets back to Coruscant and tells the senate how he met some humans on a lost world in another galaxy, he could become rich as the discoverer of humanity's lost homeworld. E.T. could be his species' version of Indiana Jones.