How could the major conflict of Arthur Miller's Death of a Salesman have been prevented?

For the conflict of the work to have been resolved in an effective manner and for Willy's suicide to have been prevented, a possible solution would have been for all the people in Willy's life who cared about him to have staged an intervention. The summary provided accurately points out that Linda is an enabler, or a co-dependent, to Willy in his dysfunctional behaviors. Linda thinks she is helping Willy by constantly propping him up and overlooking his faults. In this way she disrespects him; she helps him remain bound to his unrealistic expectations and to his delusions instead of empowering him to make necessary changes.

Linda herself is bound by years of habit and is blinded by her emotions and sensitivity; she can't bear to hurt Willy's feelings. Thus when Biff tries to speak the truth about things, she shuts him down or scolds him for not caring about his father. Biff is the one who finally begins to see the truth about their family, even though he has known about his father's infidelity for many years. However, when he realizes Willy is planning to kill himself, knowing that his relationship with his father is one of the core issues that is disturbing his father so much, he could have reached out for help outside the family.

Charley would have been a good person to bring into the the situation to provide a less biased and emotional perspective. Charley has shown himself to be a true friend, and he evidently wants to help, but unless he is given permission by the others in the family and joins with them, he can't do much except offer material assistance and try to talk sense into Willy, which only deteriorates into an argument. Happy is content with living in the same false world Willy lives in, but as his respected older brother, Biff could persuade Happy to participate in the intervention.

The solution would be to have a meeting with Charley, Linda, Biff, Happy, and Willy. First they would need to confront Willy about his suicidal ideation and inform him that he was going to get professional help, even if he needed to be committed to a psychiatric facility. This may have been the only thing that could have been accomplished in the meeting because Willy's mind was so far gone he wasn't thinking clearly. At some later point, the family would need to deal with Willy's marital infidelity and all the mixed messages Willy had sent his sons about what it means to be successful. However, the immediate concern would be getting Willy the help he needed for his depression to avoid his committing suicide.

(The links below explain family intervention and information about suicide prevention. It is clear that the family did not respond quickly enough or in the right way when they were aware of the risk of suicide.)