Remind me: how did Gcat..... happen? We see Jake's BARK journal, which is assumed to be the First Guardian genetic code, but there are no meteors sent back in the alpha session, so it couldn't have gone through the same process as Bec.
Some meteors where sent back, not a lot. The Reckoning didn’t happen but stuff that gets chucked at Skaia can still be teleported to Earth like how the Meteor got their.