It just seems odd to me, given they were released in quite a rapid manner, that they are now out of print full stop. Perhaps preparing for a Blu-Ray release?

Its probably just that the studio only paid to run a certain number of copies and once those were bought up they didn't pay for a second printing. They probably no longer have the rights so the only way the series will get another printing is if another company purchases the rights and re-releases it. Without going into too much detail as much as I like to get my DVDs on the up and up I refuse to pay $100+ for a season so I had to resort another method to get the entire series.

Its probably just that the studio only paid to run a certain number of copies and once those were bought up they didn't pay for a second printing. They probably no longer have the rights so the only way the series will get another printing is if another company purchases the rights and re-releases it. Without going into too much detail as much as I like to get my DVDs on the up and up I refuse to pay $100+ for a season so I had to resort another method to get the entire series.

$100+ for a season? Wow!
That being said, I paid $90 for the 3rd season of The Simpsons not long after it came out...