Inter is way on the different level. They beat the winners of La Liga and Bundesliga that can't be compared with PSG, which was beating the weaker teams than them. So, it totally makes sense to argue Inter is clearly a bit better, though the odds said the opposite. It only reminds me with Europa League final when Tottenham gets bigger odds, but win its first european trophy.
Your analysis is flawed. If you want to look at it that way, PSG also won against Liverpool, which happens to be the English champion. However, none of this is important. The final game is a feature between two good teams and a winner will emerge. Inter Milan may have the edge because it has won it before and has more experience in the competition, but PSG has also been amazing this season and I'm not writing them off.