“Americans” can't be made a political minority through immigration, because naturalized immigrants and, a fortiori, their descendants are Americans (and are as much Americans as descendants of 18th C and earlier British and other European migrants.)
White Americans might become a political minority, but I don't see any reason anyone but racists would think that, in and of itself, is a bad (or good, for a different stripe of racist) thing.
> Although I admit to anticipating schadenfreude when the foreign majority votes themselves the baby boomer’s assets around 2040.
I'm not sure what you mean by “foreign majority”, but whatever you mean by it:
(1) it obviously includes a significant share of the Baby Boomers, and
(2) in 2040, there will be precious few Baby Boomers for any group to appropriate assets from, and
(3) I don't see any non-paranoid reason to believe this would happen, no matter what group you identify as the “foreign majority”.
Non sequitur. Is anyone even arguing that this should be the case?
Seriously though, Elon Musk has undoubtedly benefitted from immigrating to the United States, as most immigrants do. Presumably the native born employees of Tesla and his other ventures have directly benefitted as well. Of course it’s impossible to show one way or the other that a native born entrepreneur wouldn’t have filled the same niche.
Also nobody likes to talk about the massive deleterious effects on the immigrants home countries of having their best and brightest leave.
To answer your direct question I absolutely agree that Americans can benefit from some level of immigration. I don’t believe Americans benefit from a level of migration that makes them a political minority in their own homeland though. Although I admit to anticipating schadenfreude when the foreign majority votes themselves the baby boomer’s assets around 2040.