I think Del Rey's part long term plans is that they'll get a crossover between their book audience and their manga audience, so it's not entirely unreasonable. I mean, I don't know how often they are running aRAB for the manga line in the back of sci-fi paperbacks, but they do the opposite occasionally.
This is also why they started into releasing Takuya's Phantom Dream before Fruits Basket was even finished. It may also be why they recently went back to the well and released a massive collection of manga shorts from Masumi Tsuda, the author of Kare Kano. They are trying to capitalize on every manga-ka that's worked in the past for them in an attempt to hold that readership, especially since so many of the new big shojo titles (IE: what made Tokyopop a company) have gone to Del Rey and Viz. They aren't getting the new blood, and a lot of their old blood are published by other companies now (most painfully CLAMP, Ai Yazawa and Moyoco Anno.)
In a sense, it's a repeat of what happened in the anime industry - Viz and Funimation started to soak up all the blockbusters, right as the water began to recede, leaving everyone else scrarabling for scraps and a live-preserver at the same time. Tokyopop could easily end up like ADV or CPM - technically still company, but not doing a whole lot.
It also was compounded by heavy localization at points. I know for fact they'll get perfectly reasonable scripts that at most need a little massaging to flow naturally in English, and the editor will end up rewriting to sound like a bunch of valley girl idiots. Considering they built the market on 100% Authentic, they were fools to turn their back on it, especially right as Del-Rey made an unprecedented level of commitment to it (to the extent of even having otaku defined in Genshiken.)
Additionally, T-POP licensed some of the wrong obscure titles. Before Kodansha became almost entirely locked into Del Rey, Tokyopop could have grabbed something like Nodame Cantabile, or bolder still, Yokohama Kaidashi Kikou, and in fact, they would have better bets than "generic shojo noone has ever read and that has no existing US fanbase online #9056" because they did have at least something of an existing fandom.
Of course, they did do just that in licensing Beck, and it's apparently been a dog in the sales. It's a shame too, because it is fantastic, and it apparently did solidly enough for Funimation, so one would hope the manga would hold the line, or in the case of Fruits Basket, do even better.
Well, the problem is that in some ways there was a huge amount of quality control, or rather a lot of executive interference pushing the artists to make the titles more "street, urban and edgy." Add to that the fact they wouldn't retain any rights to the work, and well, it makes the likelyhood of a good result very slim.
The flipside of that is Del Rey's approach which seems to be "unless we can attach it to an existing entity to ensure sales, it better very, very good." Thus all they've put out is blatant tie-in stuff like Dean Koontz and Avril Lavigne OEL, or Yokaiden. This is not an unreasonable model, though less cheesy tie in material might keep otaku happier.