This is true, and I tend to believe that indefinite human lifespan extension will come too late for anyone who is already an adult today including myself. But I do think that it will come, mostly as a consequence of advanced AI accelerating medical research. It may be wishful thinking to believe that it will happen within our lifetimes, but that doesn't mean it won't ever happen.

While it'd be absurd to say it's impossible, the one thing I'd observe is that it's almost certain that a precursor to anything like this would be achieving something comparable in a simpler species. And that would likely come long before we might be able to see something similar in humans. For instance the fruit fly has been studied and experimented on extensively, particularly for aging, for over a century now.

But the results remain modest. The biggest breakthrough was in the 80s when somebody was able to roughly double their life expectancy from 2 months to 4 through artificial selection. But the context there is that fruit flies are a textbook 'quantity over quality' species, meaning that survival is not generally selected for, whereas humans are an equally textbook 'quality over quantity' species meaning that survival is one of the key things we select for. In other words, there was likely a lot more genetic low hanging fruit for survivability with fruit flies than there is for humans.

So I don't know. We need some serious acceleration and I'm not seeing much of anything when looked at with a critical eye.