So, is heaven hubristic, then? Reincarnation? Both are extremely old takes, both are far more commonly accepted than Transhumanism.
Or are the Christians and Buddhists and so on also Transhumanists? Are they indulging in hubris?
We’ve already redefined things radically, multiple times, to even get to the point where “writing symphonies” is even possible.
It doesn’t have to be, strictly, forever. But arbitrarily going feeble and insane, and then involuntarily not existing, it’s not actually this deep, holistic or whatever thing.
And I think it’s incredibly hubristic to say that it’s up to you how much time someone should have with their parents still in their lives, and so on. Because once the capability for the technology exists, that is a decision that’s being made, not just dodging out of the decision and all responsibility thereof.