As for more probes - getting more speed than these did efficiently is probably hard, let alone the fact that they don’t generate personal profit probably stops them being politically viable for a while…
I only mention that to say that the motivations of people in the future will probably seem odd to us and it's possible ours may seem equally odd to them. Not odd in the sense that they are intellectually inscrutable but - like people getting excited over the matters theological - that they're emotionally inscrutable.
Could you please share the title of this book?
A new probe wouldn't necessarily need to travel faster than these to not be on Earth when the sun dies.
The idea of there being a minuscule chance the Voyager probes hit anything is fair, but even a third one of the exact same model launched in the exact same direction has just as much chance of surviving just as long, barring wild speculation that could easily go either way.
> but also any future objects sent from Earth to do the same things
As somehow saying something about the “furthest”
Here is one approach using solar sails that would get up to 22 AU/year (~6 times faster than Voyager 1):
https://youtu.be/NQFqDKRAROI?si=Ol20sGMnsEMhRVf1&t=883
...and then further down in TRL: using laser pushed light sails to get over 10% of the speed of light:
https://ia800108.us.archive.org/view_archive.php?archive=/24...
Whether humans will still exist or our planet is a glowing radioactive waste by the time the voyagers encounter a new star is not a given.