I can’t vouch for its scientific plausibility, but one of my favorite bullets to add to this list comes from Frank Robinson’s novel-length scifi exploration of the plausibility of extraterrestrial life:

“The next step is crucial. The simple organic molecules have to be shielded from the ultraviolet radiation of the primary. That requires a large body of water—an ocean—to protect them. No protection and the molecules break up as soon as they're formed. And oceans of water are … extremely rare.”

…

“But something else is rarer still. The next step in the creation of life is when the amino acids form into long chains.

Left in the ocean, they drift apart as easily as they join together. There has to be a means of concentrating them. Once a certain level of concentration is reached, they'll form long chains, more complex molecules, automatically. Heating isolated bodies of water would help, say tidal pools warmed by hot lava and occasionally replenished by the sea.”

…

“Do you understand, Sparrow? Tidal pools implies tides and that means a moon large enough to raise them—though not too frequently, because you might dilute the pool too much. A combination of the primary and the moon would raise larger tides less often, and that would be a happy medium. What's required, then, is a planet that has land surfaces, oceans, and a large enough satellite to raise suitable tides. The action would concentrate the simple amino acids and they could combine into the longer chains.”

The novel is The Dark Beyond the Stars, and I recommend it highly.

I believe this argument is fallacious. There could be infinite other ways a species could have evolved to acquire space technology. A smart dinosaur that evolved to use arms and tail could perhaps have built an industrial civilization. They would’ve been now 100 million years old! Imagine the progress. Them being wiped out probably just delayed civilization by millions of years.

> Technology continues to advance, exponentially

Why should we believe it will continue to advance exponentially? And even if it does, we many find none of the hypotheticals pans out - perhaps we advance exponentially and there is nothing feasible to reach even 0.01c

If the Alcubierre drive were possible, some civilization would have already discovered it, and we would see evidence of its use. This is certain to be the case with any kind of FTL travel, if such a thing is even possible.

But when we observe the universe we see nothing. Therefore either no advanced life exists in the universe besides ourselves, which seems unlikely, or none have spread to space in any significant degree and FTL is either impossible or so difficult no one bothers. There doesn't seem to be a secret third thing that both satisfies our observations and obeys known physics.

More like technology evolves in spurts. Huge gains within a specific area for 2-3 decades and then only small incremental advancements for the next 2-3 decades.

The fabric of spacetime itself sets the ultimate speed limit. Nothing can locally move through it faster than light. For example, gravitational waves ripple across the universe at light speed.

Anything that exists within spacetime is bound by this rule. The only odd exception people point to is quantum entanglement, but while the correlations appear instantaneous, they can’t be used to send information faster than light. Sending matter is distant second.

So, if we ever hope to travel faster than light, we wouldn’t do it by "outrunning" gravity. Instead, we’d need to find a way to manipulate spacetime itself, like bending, warping, or reshaping it ... since that, in the first place itself, is what is defining the limits of motion.

>Technology continues to advance, exponentially.

Currently focusing on imaginary money crypto schemes and ML chatbots whose data centers use as much power as entire US states, sorry.

I think our recent forays to microscopic and sub-microscopic things like computers have really distorted our views. Just look at something like EV. Give say 10x efficiency(very high) increase and we are actually still faraway from even interplanetary travel.

Physical world is big and getting from one point to other takes lot of energy and involves lot of mass.

Especially if we are actually on the cusp of ASI from self-improving AGI systems. That seems like the most likely scenario where technology emerges that we cannot currently fathom.

(Big IF there, I know)

We know enough physics to rule out any ftl travel. Assuming that is correct which seems very likely they can't get here, even radio signals is question able - even if radio signals can get here either they have already passed and their civialization (sun) is dead or ours will be dead by the time they arrive.