I would hazard a guess that the "limited time offer" was really a "limited number of licenses" offer. It's not particularly clever to advertise it that way, but it's a way for marketing to determine how much pricing affects sales as well as getting word of mouth out for the product (even if it's bad word of mouth in this case).

I'm not a big fan of the idea of limited-feature demos - I'd much rather have a fully-functional demo that's time-limited because then I have this content that I might like hanging around nagging me to upgrade.