Yes, calisthenics can be progressed to be quite difficult. Planches and handstand pushups require a ton of stabilizer muscle strength and a ton of balance. This makes them rather impressive (and fun) … but the very thing that makes them impressive also makes them rather poor at building up muscle mass. Even with advanced progressions of bodyweight workouts the limiting factor will very rarely be mechanical tension in the targeted muscle, but rather stabilizer muscle strength and/or balance. As a result, your balance and stabilizer muscle strength will improve while your muscle size will remain more or less the same.