I said the end of _artificial_ scarcity, which much of our current world, and most of it's economic system is based on. As you've flagged, the fact that entropy exists means scarcity itself will be with us until the end of time.
Capitalism can be implemented through many different complementary political frameworks/regimes, and doesn't exist outside a political system that can enforce it. Just like communism.
FDR did not have to do any maneuvering whatsoever to get his 4 terms - Grant had already run for a 3rd before him, as had Teddy Roosevelt. There was no rule against it an the people wanted him in power, so he stayed in power. Similarly, GWB didn't run for a third term, regardless of what he "could have" done. Neither of your examples are very strong here.
The point is that the US system, by itself, has no really-strong guarantees against tyrannical rule. The overall political culture of US voters is what produced the results they got, not the system by itself.
This is true in reverse too: for example, Italians have been tinkering with their electoral system for 30 years now, but one way or the other they continue to change their rulers almost every year. Systems can make some mechanisms more or less awkward, but in the end it's the shared political norms that make the real difference.
There has never been an anarchist "experiment" capable of sufficient coordination to produce modern (for its time) medicine, or the agricultural technology needed to feed current populations, or housing and infrastructure fitting of modern standards, and so on for many other goods and services we consider necessary to life today. Anarchism has almost sort of worked for a handful of small-scale, already-impovershed revolutionary/resistance groups, who can rely heavily on pre-existing infrastructure and some trade with capitalist or state communist industries, but there is little evidence to suggest it would be able to work on a meaningful scale. It also has a tendency (such as in Spain) to be co-opted by wannabe dictators anyway who simply establish oppresive state communist regimes regardless.
Soviet-style command economies are already notorious for being unable to match capitalist economies in terms of efficiency, due to the simple fact that it's far easier to use natural pricing (maybe with some interventionism) to reach equilibrium than equations and top-down production quotas. You can make an argument this could change with help from modern data science and machine learning but that's beside the point. With anarchism, you are taking all of the issues of soviet-style economies and making them even worse in that now each individual commune is responsible for coordinating with every other one it relies on. Even if you don't prevent natural currency systems from developing you still lose massive amounts of efficiency and still end up with inequality (due to resource, skill, etc. distributions being inherently different), though this time maybe you get lucky and the ienquality is between communes as opposed to being within them, between classes.
Also, there are practically no cases of lasting nonviolent anarchist revolutions. The haves tend to really not like giving up belongings and lifestyles to the have-nots when forced to. That's obviously not an argument against anarchism, though.
You make interesting assumption that centralization is more efficient then decentralisation but if that was the case then soviet style economy should be more efficient than capitalist market. In capitalism you effectively have a bunch of corporations with internal command economy that trade with each other. In Anarchism hypothetical companies are much smaller so you don't have in efficiencies stemming from these long chains of command with a lot of beaurocracy. Anarchism didn't have opportunity to create bigger project because the tendency is violently repressed by rulers of the current world. It actually eliminates the lot of losses of efficency of current society like economic rents which are proved to be negative to economy, just currently capitalism has relatively extremely strong violence potential and great propaganda machine. This obviously makes Anarchism a very hard and ambitious project but to me its clear that it would be more efficient in creating societies with higher standard of living than what we have currently.
Please consider that it can both have markets and currencies AND decentralised planning depending on what is better in specific situation.
If the size of the flung-off objects is proportional to the size of the asteroid that may be the case, but it's also possible it's mainly proportional to the force of the deflecting impact. Regardless between a potential extinction-level impact and hundreds, even thousands, of smaller, "Hiroshima-sized" impacts, the latter would still be massively preferable. Statistically the majority would hit the ocean and do little to nothing as well.
I'm going largely by memory but when the U.S. expanded copyright at one point they actually took some stuff out of the public domain. You can look it up but the current formula is authors life plus 70 and a different formula for corporate works, and when they expanded it most recently there were actually some public domain works that become not public domain retroactively. (A quick google search reveals the 1976 Act added 19 years to the terms of existing copyrights, this might be what I'm thinking of-- in other words some works that had copyright expired then had them renewed and removed from the public domain.)
There's also copyright reversion, which is a related new provision that applied to older copyrighted works. Quoting from an article I just pulled up
"...the 1976 Act created a new right allowing authors and their heirs to terminate a prior grant of copyright, the Act also set forth specific steps concerning the timing and contents of the termination notice that must be served in order to effectuate termination. The termination of a grant may be effective “at any time during a period of five years beginning of the end of 56 years from the date the copyright was originally secured”..."
But this is a red herring because the fact a model has been trained in the past doesn't mean a copyright lawsuit is "retroactive". The infringement would presumably be occuring anew every day you make it available on your web site.
