I would take some issue with the space program comparison, in that if you're going to live forever, then rather than putting up with a space shuttle that kills the crew roughly 1 in 50 launches, you have an infinite amount of time so launch that dude 1000 times unmanned to debug it fully before you send the first humans up.
Another curiosity might be if your average dude lives 500 years you may very well start launching 475 year old astronauts in that a tragedy will only cause as many lost life years as launching a 50 year old dude today.
Your first paragraph is more-or-less my point. You have an unlimited amount of time to make it safer now. Unfortunately, you don't have an unlimited budget, so the result is that you don't launch anything. Except meetings. Lots of meetings.
Anyway, what happens when you have trouble finding qualified crew because no matter how much work you put into it, it'll never be "fully debugged?" (When you're doing something new, there's not any good way to tell if the barrel is full of bees, other than sticking your head in it.)
"Unfortunately, you don't have an unlimited budget,"
Actually you do, if you model NASA as a jobs program and take an infinite amount of time.
Slowing time down by a factor of ten would have a huge number of economic effects aside from NASAs budget, but presumably you could take ten times as long to R+D and then launch 1/10th as often with no impact on progress per lifespan.
One problem from the SS program is it promised all things to all people so that would give the same jokers ten times as many chances to make ridiculous specification promises. So the new design constraints would have to be smaller than a Cessna 172, and HTOL instead of vert takeoff and the payload would be 100 times what it actually could carry, etc, at which point they'd probably find a way to blow it up 1 in 50 times again.
Another curiosity might be if your average dude lives 500 years you may very well start launching 475 year old astronauts in that a tragedy will only cause as many lost life years as launching a 50 year old dude today.