You two are clearly looking at ROS from two completely different point of view.
If you don’t need real-time and QoS, of course you will not have any reason to move to ROS2.
In the particular case of lifecycle management (point 3) ), I personally believe that without it very awful code is inevitable.
But again, if you are interested in the proof-of-concept, who cares?
This is not a a discussion about ROS2 vs ROS1 and if it was, it would be clearly “ROS1 is sufficient for academic and hobbyists use, ROS2 is trying to solve multiple important issues that many industries are very concerned about”.
About point 5), people that do need real-time requirements are (or must be) aware about the problem of priority inversion; the operative system itself helps avoiding it.
As far as i know, message passing is one of the best design patterns to avoid dead-locks.
Furthermore, real-time applications are multi-threaded and single process, not single thread as you mentioned.