Notice that I never said that Earth was atypical, just the solar system, host galaxy and our big boy star are. I think the data on this is sufficient to make these assumptions, as do most astronomers, from what I gather. Much like polling data, you don't need a gigantic sample size to figure out a general margin. However, I fully admit that there is always room for error, particularly with the cosmos.
Absolutely, but water, carbon and phosphorous seem particularly well-suited for the development of life. There's a reason that the human body has no use for silicon, which is far more readily available than carbon, despite sharing somewhat similar properties.
As an aside, the "phosphorus problem" is one of the more intriguing potential answers to the Fermi paradox.
I like to imagine the universe far into the distant future, because it will be vastly different than what we have today. It doesn't make me particularly depressed, because I'll be long dead before it happens.
Advanced civilizations are still going to be limited by the immutable laws of physics. We often hear of shortcuts like worm holes and negative mass which are little more than fairy tales, things that work on a chalkboard but fall apart in reality. I'm sure there will be many amazing discoveries, but when I hear futurists using magical thinking, my bullshit detector goes off.
I don't disagree, but I think there will always be unknown unknowns, so to speak.
