It's a question of aggregate, not specifics, and more importantly a question of politics. One need only look at the U.S. Senate and its gerontocracy of thirty-year members to extrapolate what an undying legislature would look like. The same thing appears across rulership throughout the world - nine times out of ten, if a person is making the rules, and they're significantly older than the population, it turns into a conservative anchor, as they consciously or not ground their policy decisions in the wisdom and nostalgia of their own glory days, instead of a rational appreciation of the present and future challenges.
Well, half the point of stagnating is that there won't be any challenges left. Which could be bad, I guess. :/ I think that humanity can kick up enough internal strife to avoid that, though, even if no aliens or giant space rocks turn up to wreck our shit. The future equivalent of those damn reds, forcing the millenia-old liches to either pour more money into the arms race and advance further, or die. And if none turn up, well, I think that would be an achievement all by itself. Living happily ever after until the stars die might not be ideal, but I'd say it's an okay consolation prize.
This is starting to raise some alarming questions of what, ultimately, is the point of advancing. Once mankind shrugs off death, what is there left to do? Where
should the millenia-old liches turn their undead gazes? I'm expecting some new frontier to present itself. No matter how far mankind advances, there will always be something else to do, some new threat to endure, some new annoyance to remove.
How much do you think Mandelbrot would accomplish if he had to live in Pythagoras' shadow? Sometimes radical new ideas just can't get off the ground till the old guard dies. Old people tend to be conservative, and with immortality 99.9% of people would be old (or 100%, if we have to give up children for it).
So, if Pythagoras was still alive, and had been studying the secrets of mathematics for the last 2500 years, the field would be significantly less advanced than it is now? Doubt it. Can you actually name any single radical new idea that only got off the ground because people opposing it died of old age? Preferably one that wouldn't be obsoleted by clinical immortality. If Pythagoras had clung on to his outdated ideas about the nature of numbers, he would have simply passed away to obsolescence when someone who didn't surpassed him. Happens all the time to living people.
Well, assuming that there is any benefit to being right. I'm hoping there is.
AUGH new posts! Not reading them now. This is long enough as it is.