The problem isn't just cost of living, it's that these are seasonal jobs. You will be out of work for 3-6 months of the year, so although these jobs typically pay slightly more than the minimum wage, it's not enough to survive the rest of the year. Plus a lot of these farms are in remote places which aren't that desirable for young people to live (compared to cities).

Someone else posted that around 10% of what you pay for fruit and vegetables goes to the farmers, so maybe that's where we should start to fix the issue.