Lighter, it seems you have taken some words I use and examined them in detail. I have learned some things about word usage I did not know so I thank the contributors here.

You may however be on a fools gold mission since my word selection is not groomed with a fine tooth comb nor do I measure them with a mental micrometer. I am a severely dyslexic writer, clocked and measured, and rely on associative processes not found in the angular gyrus like most people. I do not know if language for me passes through the corpus callosum or has manifested in the right hemisphere instead of the left la Brocia region. What I do know is that dissecting my fast and dirty word selection in these impromptu posts is missing the point more than I can say.

So let me do what I do most often which is pose questions.

If we take the distance to the star Sirius B and measure the additional distance that has accrued over the last 10,000 years due to space expansion and plug in speed values of a quarter the speed of light, or even half light speed,   we could determine how much more time it would take to travel there.

A science fiction writer could then assign the life span limits to an alien species by assuming their conspicuous absence may have recently been exceeded by space expansion.

There are at least 4 assumptions that with care could be whittled down but there is the reality that there will be a day when distance grows so large that only immortal beings could make the stellar trip. (organic robots?) or (hot rod gods)

This is how a science fiction writer could wrap some morsels of fiction in the grape leaf of reality and sell the plot device as the foundation for a novel.