No, you do not have to stake all trees. Generally, since we do not have commercialized dwarfing rootstocks for most stone fruits, these trees do not need to be staked. Apples are the primary tree fruit crop that needs to be staked, but not all rootstocks need to be staked; however, all trees benefit in their early life from staking to prevent wind whipping and leaning. The more size-controlling the rootstock, the greater the need to stake the tree. Trees on rootstocks that are M.9 or smaller need to be staked. Trees on M.26 and larger generally do not need to be staked; however, there are exceptions, and sometimes, it is a good idea to stake trees on M.26, M.7, and Geneva 30. Triploid varieties, such as ‘Stayman’, ‘Jonagold’, ‘Mutsu’, and others on M.26, should be staked. Varieties like ‘Gala’ or Geneva 30 also should be supported. Trees on M.7 may need support if the rootstock shank is less than 10 inches. Modern orchards planted at very high density (2 to 4 feet between trees) often use horizontal wires to provide tree support (vs. individual stakes), because it is more cost-effective and, when well-built, provides superior support. See the Apples resource area on extension.org to find more information on rootstocks and staking.
Answer provided by Rob Crassweller, Penn State University.