Del Monte went out of business because there wasn't enough demand for the peaches. The company that purchased their assets is continuing to buy 24,000 tons of peaches, but the previous unsustainable business was buying a lot more. It's the excess fields that need to be repurposed to growing something that the market will absorb.
The reason the trees are being destroyed is so they can grow something else on the land. Something that comes with a sustainable business model for the current market demands. Yes, the trees are technically going to waste, but if we had forced the peaches to be grown and canned (as many comments are suggesting) then that would be a different kind of waste as they'd sit in warehouses while the land, resources, and labor were used to produce something people weren't buying instead of being used to produce foods they were buying.
In the article you can even see that the farm lobby was so powerful that they got the USDA to pay for the tree removal. The comments talking about farmers not being organized enough or powerful enough must be unaware of how powerful the farm lobby is and how much money they're able to secure from the government every year.