I believe they do plan on having a cap on cards at some point. I think what they will do is come out with another set or 2 of cards then announce they are discontinuing the alpha set, and alpha packs will no longer be sold. It's a matter of they can't cap it till the stop selling packs. They can't stop selling packs till they come out with another set. Once a new set is out this may attract new players, so they will want old packs as well.  I guess once you get there, where do you draw the line of you can no longer purchase an older set. once a new set comes out? once 2 new sets are out? 3? 4? I think right now we just don't know the answer. We cam look at an IRL example of MTG. They have what they call blocks that consists of 3-4 sets. They typically are selling 2-3 blocks of cards for any new players who still want to join. now starting out for steem monsters that might be a bit much, but we'll see what they do. It all takes time.