Those players who are good and think can go to a better team aren't motivated playing for a team that's going nowhere! Marcus is frustrated. I don't blame him if he wants to leave. With Anastasiou & company what is PAO going to do? The club has reached its ceiling and it's the same story for 2.5 years now.
Anastasiou had 2 weeks to prepare for the Panionios match. Ouzounidis read him 100%. Blocked Berg and PAO got 2 chances for goal in 90' Berg knows football and sees what the coach is doing (or not doing properly).
I don't know what Berg thinks nor do I know what goes on inside the club. But, I played the game and in general I do know success breeds confidence and makes you produce the extra effort, whereas failures are demoralizing and everything & everybody are affected. Hard to find motivation if you have no confidence in the coach, and/or you think the team isn't going anywhere (given the expectations). Then you start saying, let me hold back a bit to protect myself... it's not worth killing myself over this....
It's basic human psychology.
In a highly competitive game, inches, or fractions of a second make a big difference. How? Well, by running a little harder, putting your foot or you body out to block a shot, fighting for the ball, being motivated.... Now multiply this by 11 players on the pitch and the game takes a very different course.... ;)
Obviously not all goals are preventable, but ... You see how so may goals PAO conceded because one or more PAO players weren't putting 100% of effort. Now, go down by a goal or miss a good chance or don't create chances because of lack of effort, and the game is lost. It's as simple as that.