It the natural progression of the business. I've been a consultant for home video releases for over 20yrs - starting with Beta/VHS to Laser and now DVD. Companies just throw out these releases and when they fall into a lower realm in purchase they re-issue them at a lower price. Another reason for lower prices now is that many companies are planning to get into HD (either Blue-Ray or HDDVD) so they are trying to get rid of stock on the current non-HD format. This not only true for TV shows but for films as well. Notice your Best Buy and Circuit City ads, many film that sold for $20 are now available for $9 or less! The amazing thing here is that there are shows with elements that simply won't stand up to the new HD format. STTNG is one - the first few seasons were done on video and transfered to film which is why they look soft and have muddy color. There are quite a few shows produced in the 80s that were done this way to save money. If anyone has seen the DVD release of FOREVER KNIGHT it almost un viewable due to this.
TV on DVD has also taken off due to lack of studio product. With so much already available studios are scrambling for product. They shut their doors to smallr companies who used to release product the majors didn't want to be connected with. It's harder and harder for smaller compnies to get studio "B" and "C" ttles, and it has been for a fews years now. The studios turned to TV shows to fill the gap in their release schedules. Also, with more and more cable stations sprouting specializing in wacky and extremem interests the demand for product opned the flood gates for the studio to reach back into their vaults. Mastering entire series, some of which need restoration, is a costly endenver. To aid in that releasing them on DVD is a natural step in regaining that money. To the consumer it may seem weird at how much product is available and even why it would be - for the studios it just business as usual.
