

a lot longer than that.
Synthetic corundum, spinel and others have been around for over 120 years, and optically transparent uncoloured sapphire glass for over 80 years. They are just aluminium oxides.
ALON is just the new hotness, and not as good as some others in terms of visible light transparency.
If it is possible to make small amounts of those elements on purpose as a byproduct, it can help to offset the costs of the reactor in some small way and help with isotopic/nuclear research in general. But that can be done in pretty much any fusion reactor design to some degree.
As for Alchemy of the future, If in a thousand years we can just built whatever materials we need (including potential ultra heavy stable elements) from raw subatomic particles we don’t even need mining, just gather up some hydrogen/helium from space and transmute it into whatever you need. food, fuel, structures, etc.