Because Alonso is from Mineoro and Mineoro launched this device in 1985.
I don't believe Garret was gangster enough to point a gun into Alonso's head demanding cloning, do you?
Anyway one my team members still owns one of these original pearls from 85.
We are modifying it right now.
PS.Ah... Almost forgot to remind that a few weeks after the Garret factory episode, Alonso was invited by Mel Fisher to climb aboard his ship. A few days later Alonso's device detected the Atocha's motherload.
Since Mel is deceased, anyone can check with the Fisher family about this one.
But trully, I don't expect them to release such info as since that time they tried to hide this info as they could in order to keep Fisher's 'glory'.
This in fact was one of the reasons that caused the british member of Alonso's team to die from disgusting.
But this is another story.