Why does Willy Loman committ suicide in Death of a Salesman?

There are a number of reasons why Willy committed suicide, but we are never given specifics. First, there's his job. He's no longer effective, the younger men are passing him by, sales no longer rely on the game he was taught as a young man; Willy had been replaced by those with new ideas and techniques, while he refused to change with the times.

Secondly, he was in debt over his head. His desire to acquire the American Dream left him with a lot of things he couldn't afford and not enough money to pay for them. Without a job, all of these things became a pit he couldn't crawl out of, and in his own words,"you end up worth more dead than alive." (Page 76)

So, I believe that these factors, along with regret for the things he'd never done, and also a fear of growing old contributed to his suicide.