1. J-20 is in serviceThe best part is when Justin Bronk speculates that J-36 has grown out of the JH-XX program because 14 years are too short to go from 5th to 6th gen fighter development. This just shows he doesn't even have a basic grasp of PLA procurement and development doctrines.
One of the most fundamental PLA equipment development doctrines is "服役一代、研制一代、预研一代、探索一代"
In English, at any given time for a given type of equipment:
1. One generation is in service
2. One generation is in full development.
3. One generation is in preliminary research and feasibility study
4. One generation is being brainstormed.
Chengdu was already researching the next-gen fighter program before we first saw J-20 in 2011. Just like they were already researching J-20 when J-10 first flew in 1998.
2. J-36 is in full development.
3. J-40 is in preliminary research and feasibility study
4. J-50 generation is being brainstormed.
Let that sink in. China is moving on to design J-36's successor already.