I can't say I'm not disappointed, but I understand the (arguably unfortunate) realities of this world.
The main thing that bothers me is that, if I'm looking into this correctly, it's only the new version that will have Mac support, correct? Although I feel as though I haven't the right to complain given that I did buy the program when it was on sale, I did buy it having been told that there would be a future update to include my primary OS. I do have a Windows partition, which avoids having to deal with the rarely-functional WINE or Parallels or whatever, but it's still an inconvenience and it's a little disheartening to hear that I'm never going to get that port.
I'll still probably end up buying US3 once it goes on sale; I'm not sure. Depends on how much the full asking price is and how well it would perform on my computer (US2 isn't great in that regard, at all).