Yes, they were in the same position. City started the season strongly, Liverpool started the season badly. City absolutely collapsed, whereas Liverpool picked up and were the second best team in the league the second half of the season. Clearly different trajectories. How can I look at a team 25 points behind and say the were quality? The same core team managed to get 97 points the following season, with the major acqusition being Alisson (or at least the major difference maker). That's why.
Yes, it's true that Liverpool weren't tipped for the finale beforehand, but they got there and looking back at it now it's not that weird even if it was a bit a surprise at the time. City's semi final run, though, is obviously much more of an outlier and less indicative where they actually were as a team at that point.
Because it showed they were building towards something, how can this be so hard to understand? I mean, we literally have the facts here and we know Liverpool results were insane from the start of the following season.
I don't think this is a great way of looking at it, combining squads won't always make the teams that much better. Anyway there clearly are quite a few players in the Liverpool side that City gladly would have taken. Salah, Mane, van Dijk and Robertson at least. Alexander-Arnorld I'd say. I think they'd have Firmino in a heartbeat as well (I don't think Liverpool for example would have been that much better with Aguero in that position instead of Firmino during those years even if Aguero obviously is the better player). Neither GK were impressive. Kompany would be the other CB position. In midfield City is generally stronger of course.
Kompany, Sterling, Aguero, Fernandino, De Bruyne and SIlva are obviously all very good players. Sterling was more a prospect than finished product though and greatly imrpoved during the coming three or so years. Fernandinho isn't as good as a lot of people here make him out to be, but he's a very good DM and does what Pep wants him to do very well. Kompany didn't really play that much under Guardiola though, he was injured most of the time. The other three were world class, no doubt.