Ardoush,
These are good points and often instructors do "lose" the students in classtime. This, however, should not happen. Class time should be used for those activities that require other students, collaborative discussions, planning, presentations etc. The actual alone work time should happen outside the classroom. Even for online classes, there should be real time chat sessions which help keep the students interact and work together in real time as well as the asynchronous activities that can be done outside of those times.
Dr. Ruth Reynard