Well yes, the economic argument isn’t the strongest one.  The strongest argument is that the alternative is becoming weak, helpless, and mad, followed by literal involuntary permanent nonexistence.  There are very few arguments that would convince me that we should not develop immortality technology when I have a metaphorical gun to my head that can only be moved farther back by immortality technology.

You don’t find the economic argument compelling, I don’t find “really, death isn’t that bad” plus all the other arguments compelling.  The price I am willing to pay for this technology is very high.  My enjoyment of the future beyond the end of my lifespan is literally zero or null if it is not developed.  

That price includes authoritarian restrictions on reproduction.