Podcasts and videocasts are a nice idea.
I think the practical consideration is both storage space and bandwidth. The costs for Web server capacity could be very expensive.
NAPP is doing podcasts and Photoshop TV. They found it to be so expensive, they had to find sponsors to help defray the costs. Michael strives to keep his site free from advertiser support so there is no question about his views being independent.
Something like 50GB of bandwidth sounds like a lot. But even without podcasts or videocasts, my own site generates 10-20 GB of traffic each month from downloading action sets and PDF tutorials. Going to forums with lots of images, podcasts, etc. would quickly exceed 50 GB a month. I have no doubt that Michael's site would experience even more traffic.
I know there are ISPs that offer unlimited bandwidth, etc. The problem is then either storage space or how many users can access the site.
I have no limit on traffic with Interland. But I only get 50 MB of storage, for example. They do that on purpose to limit multimedia. The other limit is that the site is on a shared server. So, if traffic gets too heavy, throughput will slow down. There's always trade-offs, unless you are willing to pay more than site without advertising and the like can ypically afford and remain free to all who visit.
If Michael did decide to include videocasts and podcasts, I'd be pleased.
I'm not disagreeing that it would be a very welcome addition to Michael's site. I just believe there are practicalities that get in the way of implementing it.
Perhaps you know of a low cost way of implementing your suggestion? One that can reliably serve simulataneous access by dozens of people? I'd be interested, for my own site.