So does that mean there are packs that I can no longer buy? And there will be packs with limited availability?
There are some discontinued packs. The Kickstarter and alpha packs are gone. This doesn't prevent us from making things that are kinda similar ish but we won't do it quite the same again.
The current packs and future packs aren't exclusive and aren't guaranteed to come back. Basically if people ask for specific ones we might resurrect them.