Because eventually there will be an asteroid or nearby supernova that will destroy civilization unless humanity’s total wealth and technology have improved vastly between now and then. Stasis is death.
I think doing so would introduce far more risks to them. Space ain't friendly.
Beyond that I find it hard to care to drive anyone to work their ass off today for whatever humans are around 100+ years in the future. And, of course, more technological development brings more chance of mass self-inflicted die-off of humanity anyway. In 1900 it would've been much harder to kill 10%, 20%, 50%, 90% of the global population than it is today.
Everything is death eventually. And predicting the future is hard.
That’s not what I’m advocating. I’m not even proposing a global prioritization of goals. What I’m advocating is simply to not attempt to slow or halt the progress of technology.