Like MVP has said in the past, WAR doesnt take roster/team building into account, which you are also kind of agreeing with here. I would agree with that , but I would be shy to agree that a retrospective view of past makes theoretical performance predictions fully dismissable.
If I look at Roman Anthonys projected WAR or WRC+ or OPS or RBI totals, I dont immediately dismiss them because hes never done a full season. I take them with more "gain of salt" because sophmores can slump, get hurt, and sure - the chance of superstardom from a second year player who didnt play a full rookie season would be generally lower than the chance of superstardom from an established superstar (holding many things equal for apples-to-apples comparison).
To me the issue here is opportunity cost. This team looks like it has/had the potential to jump from T2 baseball team to T1, and I dont think we've done that. And I can understand being disappointed about that.
Right now , this team has about a 59% of making the playoffs, and I do think thats a lot because of the expanded format. But you could argue that the expanded format leaves a lot of teams/owners complacent. Because there is nothing worse than falling out of contention early, but with so many teams making the playoffs, thats kind of hard to do. Thats also why deadlines arent what they use to be becasue there are just less sellers because its easier to make playoffs due to expanded format.