There is no absolute in terms of "full potential", only further growing sales and popularity.
Not necessarily, it means that WotC choose to grow in a certain direction and this has proven very beneficial to themselves. But there is no wall here, they did not run into any, nor did they create one for themselves. If I have land in many directions, choosing to exploit one direction (and being successful in it) does not mean that I build walls in the others, just that I choose not to exploit them (possibly for very good reasons).