FS2's ending was an opinion, FS1's ending was 'understanding' of the Ancient theory.
"All the jump nodes from Earth are gone, but the Shivans can rebuild them. I'm told we can expect them again, but not in my lifetime."
We never observed the Shivans rebuilding a jump node in FS1 (or FS2 for that matter) so that's purely speculation. And the Shivans returned within the lifetime of characters in FS1. So it's opinion/speculation.

And speculation can be proven wrong. Karajorma and others have pointed out that if FS2 had never been made, post-FS1 campaigns would have focused on the Shivans rebuilding the node to Sol.