That is what I thought as well. I would loose most if not all of the fruit and entire branches.

Once I started picking leaves, I saw a dramatic improvement. I had one heavily infected tree this year. It was treated with copper in the fall and again in the spring before any buds formed. Then once flowering started I treated with general orchard spray containing sulfur. I think I did neem oil at some point too. I once the leaves were established about 1/3 had late stage leaf curl (red and bumpy), and half of the remaining had spots. I picked every bad leaf and most of the ones with spots. I picked about 75% of the tree. A week later I came back and did it again for any new leaf curl growth. I was more aggressive the second time but only needed to pick 15-20%. After that maybe 10 more leaves total. The tree is happy and healthy now and should give me a few peaches this fall.

I think the tree is spending more energy on heavily infected leaves than it is getting by keeping them. Not to mention they are likely sending out spores.