... discontinue the production of ref 116900 Airking, or of ref 214270 Explorer or of ref 116500LN Daytona?

We don't know and all that helps here is either the view in the crystal ball or wild speculation. Yes, but when it comes to vintage watches, these are already discontinued and even more interesting than the fact their quantities are fixed, is the point that their quantities are usually much, much lower than these that are machine produced for actual references nowadays.

And when throwing an eye on vintage gold watches, it is even more interesting: these are not available in a stable quantity but their numbers are constantly decreasing because of the intrinsic value that is extracted by smelting the watch, by people that don't care about the art and beauty condensed in these watches -- sad but true.

Now, the bottom line: what you hope for your latest acquisition is already a fact for vintage watches -- they are no longer produced. And they are worth it being protected and collected -- Plus Ultra.