That gets me too. Before I decided to collect them Neo 1 boxes were ever-presents on eBay. Since I got the first box (June 2015) I can’t really recall any opportunity to buy or enquire about one, yet I was able to get two Neo 3 boxes and one Neo 4 box, and with the exception of those three, I’ve never seen or heard of any sealed boxes of those since I’ve been back in collecting (mid 2014), save one or two Neo 4 boxes that have been opened by people. Though I’m sure perhaps some people here might have a secret stash somewhere!
Also, I see you share my strategy of acquiring the Zard in PSA 10 and everything else in PSA 9 - along with keeping consistency in stamps. Besides our preference for thicks/thins, we’re exactly alike.
Not a complete set but all three have recently been put into new PSA cases, and my scanner fits three cards nicely. One of my goals for 2017 is to get the other two. Beautiful cards. I decided not to pursue a complete Gold Star set any more and either have sold ones I did have or am in the process of doing so. The only one I’m debating keeping is Charizard, but I am also saving for a house so I may end up sacrificing it.