I have no idea what you mean by case in point rmt have units at a te:usd equivalent. Every rmt trading post I see in the website that shall not be named uses an exchange rate less than .40 and many sell te for that as well. While I'm not gonna argue the merits on demerits of real money trading I can tell you very few rankers (and I know a lot of them) sit there and think 1 te = 1 usd so their 7 stars are worth 10s of thousands of dollars.
I think a couple of things have happened to 7 stars... first, the game has become very focused on gw. As that has happened, cheao substitutes for cards (lierna for sparda, eclipse/soica/ophelia for alondra) have drven the pricesnof the superior cards down... I remember sparda being worth Frene + 1k when Frene came out and Alondra Frene + 700... Now Frene which has 100 prints but is useful in gw and doesn't have substitutes is often priced higher than those 2 cards, another interesting thing in the game and dynamics nobody really wants to discuss because it relates to rmt is that rankers/people with 7 stars have started to do their own quit sales. Even 2 months ago I remember trying buy alondra for 2k te... Nobody would sell... I'm certain that if there was 2 quit auctions with her she would have dropped to 1500 but with nobody quitting and FoiledFailure buying out all the quitters and then effectively controlling prices, card prices just didn't fall. The first shift was to people who wanted to quit price checking high (Madeleine 3k) and then selling low (1.7k, you've gotten a super deal) but as more and more quit auctions happen there's true price discovery and the real supply and demand is displayed. As a result more people have gotten frustrated and quit which is kinda funny.
Anyways, sorry for rambling but I do find it very interesting what's happening in fanta.