You guys know how animals age differently suppose to others? Same could be applied here.
Did you know turtles can live over 200 years old? Dogs live shorter lives than humans, because they age faster.
Putting biology aside, it wouldn't surprise me that some alien species live longer/age slower than others. I heard a while back somewhere that Lombaxes age about every 5 human years and during the 2nd PS2 Ratchet game I believe he was 3 1/2 in lombax years, which would be 18 for them. This however was a few years back, so I don't know if IG changed this in anyway.
Also another thing to point out is while Ratchet seems like an adult to us, he may still be a child to others in his race. Alister seems like he's in his 70's-80's, but putting the theory that Lombaxes age slower, he could be waaay over 100 years. It kinda would make sense if you think about the years than went by from during and after the Great War, Tachyon attacking Fastoon and Ratchet finally meeting Clank for the first time. What seems like a long time for us could be shorter for them.
As for how long Tharpods can live, I really have no answer to that being I will need to replay the game again to put everything together. I'm not sure but I heard that Ephemeis was a round for over 100 years, but it attacked Uzo City after some time.
Guess I need to do another run.