I still remember those days when the lecturer wrote his notes on the blackboard from memory, and proved complicated theorems before the classroom without any aids to the memory. Is this gone? And is it a bad thing?

I believe that Learning by PowerPoint will be increasingly common, and generate increasingly worse results. Those students who have personal access to more experienced colleagues will probably do all right, but those who only have access to the PowerPoint presentations and similar things will not learn much about studying the world.