Who do we often often blame to be responsible for the failure to deliver, is it the coach or the players, because the two plays the most important roles towards the performance of a team in winning or loosing a match play, so let's discuss about who's responsible and should receive the blame.
You're the one who should be blamed because you can't accept if the team you bet not play as high as your expectation, so lower your expectation please. 
I think that everyone is responsible because the team is a single entity. However, I am a fan of team sports and even often bet on them. I never feel negative emotions even if they lose because I understand that there are many factors that are simply impossible to determine for a victory. Even if we take them all into account, the wind blows in the wrong direction or the main player gets an old injury and the game goes in a completely different direction. Personally, I am never going to blame for this, even if I lose money on bets.
I agree, people only see the coach and the players, but the team is built by many people behind that. Starting from the scouter who sign the player, the owner who can afford/willing to buy the player, the private coach to train the player based on their position. Then the coach who train the whole squad that will play as his imagination.