There is an audio podcast, every week available on the blog of cloud.blender.org . A stream would require more work.
They will have to prepare .blends, to be more formal about topics.
In a sense, we already have one place that is grouping what you are talking about. It is the cloud.
One of reason to subscribe to cloud is to have access to training material.
So, you can not expect that they will deliver everything useful to know on a subject in one stream.
Yes, a demo of new feature is always cool. But sometimes, there are a lot of dev work for underlaying stuff and nothing to demo until a last layer of UI code is done. And sometimes, to demo the effect of a checkbox for a cool feature added by a patch by a dev from outside of studio, they have to build a content that can be shared.
So, it is easy to ask a video stream. But we can not deny that is more work for them and less time for doing something else.
When they are doing an open movie or an open game ; they are already sharing everything.
OK ! Yo Frankie! is old. Probably, no course about archvis exists on the cloud.
You can not really expect courses about game now. There are two Open Movies on schedule of 2018. (Hero and Spring)
And it is not pertinent as long as no 2.8 release arrives. Sincerely, if you want stuff about realtime work, you want it done with EEVEE.