The main reason there's not more good-quality mainstream video content available for free on the web is bandwidth cost. A TV series of 12 one-hour episodes compresses down to about 6GB at moderate quality, perhaps four times that for good quality. 6GB of server bandwith (bought in bulk) costs about USD0.6 today, so 100 downloads a day would cost them $2000-$8000 dollars/year. For one 12-hour series. Philanthropy's fine but the owners probably aren't willing to spend that sort of money to 'give away' their no-longer-commericial material.

However, the P2P file-sharing model changes this. People 'pay' for receiving content by in turn sharing files they have found worthwhile themselves, donating whatever bandwith they can to allow other people to download the file from them. So, in the above scenario, the owner of the material can make their video available for a small fraction of the cost of putting it on a web server. They can even put magnet links on their web-site to 'link' to the files extant on the gnet.

If you know there's material out there that people would like to share but can't afford to, suggesting to them that they make use of somethign like Gnutella's a service to them, the file-sharing community, and the Internet in general.