175 years isn't a lot of time when we speak in humanity's time scale. We've been around 200,000 - 300,000 years.
That alignment will happen many more times in the history of humanity. That is to say, I don't know if a spacecraft to overtake Voyager will be launched on the next alignment or one 10,000 years from now, but it doesn't seem unlikely to happen.
If humans survive 1000 years I can’t see any way we haven’t populated the solar system and can build probes which travel far faster than voyager, including self sufficient asteroids
Once we leave the solar system in a self sufficient way I can’t see any event which would cause a species level extinction
I admire the confidence but a bunch of meat bags prone to bacterial and viral infection, impact damage and with limited use by dates would need some serious luck to survive a simple impact on earth let alone living in cans around the solar system. If we don’t mess our nest so much that we make it uninhabitable. We’re stuck here with short term horizon psychopaths pulling the strings remember.
A give colony would fail, but if there’s a thousand colonies and 99% fail that’s still 10 which don’t and can recover