Terrywoodenpic
Oldest Heretic
False. Many long lived isotopes that are claimed to have once existed are claimed to have disappeared. You can compare nothing at all that is not already here right now. The issue is how it got here. NOT how it now behaves and decays.
No problem at all as to how they got here they were all formed by fusion in previous generations of stars.
This is an iterative process starting from Helium.
We and everything else are Star dust.
Of course all radioactive isotopes slowly decay to something else. This starts from the day that they were formed.
It seems that all the ones found on earth were formed at the same time. which would suggest that all the earths material came from the detritus of the same exploding star.
Which is reasonable considering the distance between such stars. and the expanding universe.