That seems to indicate that summarizing what they've said as the average age of death being 72 years is not accurate.

Not far indeed: global life expectancy at birth was 26 years in the Bronze Age, and in 2010 was 67.2. Five years ago our life expectancy at birth was more than double what it had been.

This is a little misleading because low life expectancy at birth was to a large extent a function of very high infant mortality. It is true that even if one takes into account infant mortality (for example by looking at life expectancy at three years of age) that life expectancy has gone up. However, this is primarily average life expectancy. Maximum life expectancy has barely budged. This is sometimes referred to as rectangularization of mortality curves.

I do think it is likely that we are going to see substantial improvements in maximum life expectancy in the next few years, but the change in life expectancy up to this time isn't really indicative of it.

Good analysis! A few remarks:

In practice even for a planet with as thin an atmosphere as Earth, getting past the atmosphere is more difficult than actually reaching escape velocity. One of the most common times for a rocket to break up is near Max Q which is where maximum aerodynamic stress occurs. This is generally in the range of about 10 km to 20 km up.

In worlds too big to escape by propulsion, people may come up with the idea of the space elevator, but the extra gravity will require taking into account the structure's weight.

Getting enough mass up there to build a space elevator is itself a very tough problem.

Some world out there may have a ridiculously tall mountain that extends into the upper atmosphere. Gravity at the top will be lower, and if a launch platform can be built there, takeoff will be easier. Of course, this is an "if" bigger than said mountain.

Whether gravity is stronger or weaker on top of a mountain is surprisingly complicated and depends a lot on the individual planet's makeup. However, at least on Earth-like planets it is weaker. See here. Note though that if a planet is really massive it is less likely to have large mountains. You can more easily get large mountains when a planet is small. (e.g. Olympus Mons on Mars).

India has a huge coastline, but for mythical/cultural reasons, Hinduism used to have a taboo against sea travel. In the worst scenario, our heavy aliens may stay on ground, not because they can't, but because they won't; maybe their atmosphere looks too scary or their planet attracts too many meteorites or it has several ominous-looking moons or something.

This would require everyone on the planet to take this same attitude. This seems unlikely to be common.

Or there are fewer civilizations than we expect, or something is wiping out civilizations once they go to space, or most species for whatever reason decide not to go to space, or we are living in an ancestor simulation which only does a detailed simulation of our solar system. (I agree that all of these are essentially wanting, your interpretation makes the most sense, these examples are listed more for completeness than anything else.)

Anyone want to take bets on whether or not this will turn out in ten years to be natural?

I don't think this conversation is being very productive so this is likely my final reply.

Just answer me a simple question.

? How do the first 1000 naturals look like, after mixing supertask described above has finished its job,

You may say that this supertask is impossible.

You may say that there is no set of all naturals.

The resulting pointwise limit exists, and it gives each positive integer a probability of zero. This is fine because the pointwise limit of a distribution on a countable set is not necessarily itself a distribution. Please take a basic real analysis course.

I don't give a damn about infinity. If it is doable, why not? But is it? That's the only question.

I'm not sure what you mean by this, especially given your earlier focus on whether infinity exists and whether using it in physics is akin to religion. I'm also not sure what "it" is in your sentence, but it seems to be the supertask in question. I'm not sure in that context what you mean by "doable."

Then, a supertask mixes the infinite set of naturals and we are witnessing "the irresistible force acting on an unmovable object". What the Hell will happen? Will we have finite numbers on the first 1000 places? We should, but bigger, no matter which will be.

The "irresistible force" is just an empty word. And so is "unmovable object". And so is "infinity" and so is "supertask".

I'm not at all sure what this means. Can you please stop using analogies can make a specific example of how to formalize this contradiction in ZFC?

The topic is also exercised here:

http://mathforum.org/kb/thread.jspa?forumID=13&threadID=2278300&messageID=7498035

This seems to be essentially the same argument and it seems like the exact same problem: an assumption that an intuitive limit must exist. Limits don't always exist when you want them to, and we have a lot of theorems about when a point-wise limit makes sense. None of them apply here.

This is not at all an attempt to banish infinity in any general sense.

Of course it is. Nothing infinite has been spotted so far.

I'm not sure how your sentence is a response to my sentence.

This is rhetoric without content.

Is it? Is this same "rhetoric" against aliens also without a content? If I say that people want aliens, because they have lost angels, is this really without a content?

Not only that there is no infinite God, even infinite sets are probably just a miracle.

Generally, yes, the content level is pretty low. It essentially amounts to Bulverism, where one is focusing on claimed intents and motives rather than focusing on the substantive issue of whether there's an inconsistency in PA or ZFC that can arise due to issues with supertasks or other ideas related to infinity.

It may well be that specific people or groups are adopted aliens in a way that is essentially replacing deities. The Raelians and other New Age groups certainly fall into that categoyr. But it is a mistake to therefore claim that in general, people believe in aliens as a replacement for belief in a deity. And it is an even more serious mistake to make such claims about infinite sets. If you see physicists praying to infinite sets, or claiming that infinite sets are responsible for the creation of the universe or humanity, or claim that infinite sets will somehow save us, or claim that infinite sets have an agency to them, or claim that infinite sets have a special mystery and majesty to them that merits worship, or if they start wars with or excommunicate people who don't believe in infinite sets or believe in a different type of infinite set, then there would be an argument.

Ah, yes, I think that makes sense. And obviously a proof of say Friendliness in ZFC is a lot better than no proof at all.

I'm not sure what you mean by this, and in so far as I can understand it doesn't seem to be true. Physicists use the real numbers all the time which are an infinite set.

https://physics.aps.org/articles/v2/70

The problem there is that certain specific models of physics end up giving infinite values for measurable quantities - this is a known problem and has been an area of active research since early work with renormalization in the 1930s. This is not at all an attempt to banish infinity in any general sense.

Now, when there in no God, the Infinity is its substitute, most people would love to exist. But it's just another blunder.

This is rhetoric without content.