As you say the obvious crimes of both sorts of bad talk are easy to avoid. In my experience however grad students get nearly no feedback and training. A little bit can go a long way. In particular they can then recognise their own weaknesses and choose a style that minimises them. I am not talking mastery here, just guidance to tell which of the many common traps that particular person falls into.

As for rooms with no blackboard/whiteboard at all, that is horrible. I am teaching in a lecture theatre like that at the moment and it is a nightmare.

Of course powerful tools are always good to have around, and in an ideal world everyone would learn to use them well. In the real world, people are influenced more by the affordances of the technology they use — and there is empirical evidence that some of them, while enabling better talks, encourage worse ones.
Taking away laptops was obviously hyperbole, since it can/will never be done. But alerting speakers to the predictable perils of PowerPoint — its linearity, one-sidedness, rigid format, etc. — might, if not turn them away from laptops, at least give us better laptop talks.

I return to my point, the story is the key, work out the best tools from that. This lies at the heart of all the articles you cite. I agree with them. I just do not agree that laptops make things worse. We need to give more graduates training in how to present and then marvel and the wonderful variety of ways in which that enthrall us with their research. Not take away powerful tools because they can be used badly.