Salaries for fruit pickers didn't go up because demand for fruit pickers didn't go up. The farmers knew that they were screwed no matter what they did- if they paid the pickers more and tried to pass the costs on, they wouldn't be able to sell the fruit, and if they paid the pickers more but ate the cost, they wouldn't actually net a profit. So they were going to lose money no matter what, and did it in the least-impact way possible (let the fruit rot).