So i decided to compare everyone to their Baseball Prospectus PECOTA projections - which not only give an average, but percentiles (90th, 80th, etc.) so that you can get an idea of just how far above or below expectations each player has performed. This isn't a perfect exercise, but I'll try to balance BA, OBP, and SLG for each hitter. "50" means, essentially, meeting expectations
Altuve: 90+
Rasmus: 60/90/60 - give him a 70
Springer: 50 across the board
Castro: 30/90/40... call it a 50+
Thus ends the hitters meeting expectations.
Correa: 20/70/20... could generously be given a 40
White: 20/10/70... again, could generously be a 40
Marwin: 20/30/60... another sub-40
Gattis: 40/60/20 = 40
Valbuena: sub 10, across the board
Tucker: sub 10, across the board
Marisnick: sub 10, across the board
Gomez: subterranean across the board
That's 4 guys not meeting expectations, and another 4 that have fallen short of BP's worst case projections.
Pitchers are a little easier to handle, going by ERA alone:
Harris: 90+
Devenski: 90+
Feldman: 70+
Neshek: 70
Fister: 50
Gregerson: 40
Sipp: 20
Fiers: 20
Feliz: 10
Giles: sub-10
Fields: sub-10
McHugh: sub-10
McCullers: sub-10/Inc.
Keuchel: sub-10
So that's 9 guys on the team meeting expectations, with only 3 of those being wildly pleasant surprises.
If you look at the others, you have more players that have fallen short of the worst-case scenario than have actually met expectations.
I don't see how you blame the manager or the GM for this. Nobody could have foreseen half the team just completely falling to pieces.