I think the issue stems from initial flight training and won’t be fixed by mandating manual flight in airliners. I see pilots who “practice” manual flight often who are still bad at it, pilots who don’t practice much at all who are very good when their skills are called upon, and everything in between. Manual flight once the aircraft is cleaned up and climbing is tedious and I don’t particularly want to be forced to do it. If you want good flying skills, make aerobatics mandatory part of flight training. Even then, some folk just aren’t all that gifted when it comes to flying and no amount of practice or training will fix it.