Yeah, red delicious, macintosh, and granny smith used to be good, but all of them got changed into terrible apples – no flavor, often bitter, and a mushy texture, but they shipped well and stored well as in you can’t tell until you bite into it if is this year’s new crop, which is usually pretty good, or if the store produce buyer bought the leftovers from last years crop, because profits.
To answer the above question about breeding when you’re not going from seed, apple trees are usually sold as a chimera of two trees: a root stock, which determines the height of the tree and disease resisstance, and grafted on fruiting wood, which has the leaves, flower buds, and fruit. Some new apple varieties are bred by cross-polinating different species, growing the seed until the sapling is of graftable size, grafting that onto an existing apple tree, and evaluating the resulting fruit. For an existing variety, there are enough mutations whenever a tree puts out new growth that sometimes the fruit that results is just different enough to be worth cultivating and selling as new grafting stock – this is what happened with the Red Delicious, someone noticed that a particular red delicious tree had fruit that lasted longer and didn’t bruise as easily, so would be better at surviviing shipping and so on.
These new growth mutations are much less variable than cross pollination, relying on replication errors at the genetic level during growth, much like cancer. This is, of course, ignoring any attempts in induce mutation via gamma garden, chemicals, CRISPR, or other artificial means which are surely used these days.
