The only hurdle is the ooh-scary genetics business caused by lack of knowledge and too much crappy fiction
Are you serious? Are you disregarding the other, more serious reasons? Trying to support genetic modification by ignoring the real issues involved is just as bad as trying to oppose it by making issues up/exaggerating the ones that exist.
You're right about "lack of knowledge", but in more ways than you think. It's not just the general public being misinformed, it's the fact that genetics is
still a very young science. It's not nearly as ideal as you'd think it is from learning about it in high school biology class, a lot of things simply aren't understood about it, and it would be flat-out irresponsible to start widespread human experimentation on the genetic level at this stage.
This isn't even considering the social and ethical problems. Genetic engineering technology is
not well-regulated like more established technologies are, and people (yourself included, apparently) seem to disregard the social/economic questions involved when considering the possibility of genetic modification being available on the free market (Do you actually want to see the upper classes, or indeed entire nations, become genetically superior to others? Do we really need that?). There are a lot of legitimate concerns regarding genetic modification to human beings, or even genetic
screening, for that matter. It's nothing to dismiss out of hand simply because the technology has potential. People have done that with new science/tech in the past, and it has caused problems.
Some people will want to live to and beyond the heat death of the universe, and who knows what technology will be able to do then? Escape into an alternate universe? If there is even the slightest crack in the door of a law of physics, it's engineering's job to push that door wide open. We shouldn't be thinking about what we can do, but about what a vast intelligence could do (this argument is similar to the one for FTL communication). I want do die because I don't want to live anymore, not because my body degenerates.
If you're going to bring breaking the laws of physics into the argument, then there's no more argument, because you're engaging in totally hypothetical and baseless speculation by providing absolutely no limits to what you think might happen. Sure, maybe we're wrong about the laws of the universe, and maybe entropy doesn't work the way we think it does. Or maybe there's a God and an afterlife. Or unicorns. Or a giant disembodied head that swallows us up and reincarnates us
as unicorns. When you start essentially pulling stuff out of your ass like this, it doesn't make for good debate, and it's fruitless to talk about.
We have blood substitutes efficient enough to let you sit under your pool for an hour. But nobody ever thinks of replacing some of their blood with the substitute.
- Definitely going to need a source on that.
- Even if that's true, is it as good as human blood as other things? Hell, it doesn't even make sense to "replace" human blood; blood does many more things than carry oxygen. Even if it only replaces that function, what side effects does it have? What would its long-term effects be? And so on.
Thing about the laws of physics is, there is no crack.
I recommend Asimov's The Last Question, by the way. In entropy, sure, there are no loopholes. But at least theoretically, it may be possible to escape this universe into one in an earlier stage of its evolution.
No, it's not. That's not theoretically possible. In fact, it's pretty explicitly
impossible.