The only reasonable explanation for the delay is cost.
As far as I can make out, there are only four languages with the 2013 NWT that have more than 100,000 JWs: English, Portuguese, Korean and Italian. English and Portuguese versions were released in 2015 before the financial crisis struck. Korean was released even earlier.
Languages with more than 100,000 JWs that have no new Bible include: Spanish, French, German, Polish, Russian, Japanese, Tagalog.
There is no conceivable reason why these languages should take years longer to produce than Gun, Ewe, Amharic, Dutch and so on, other than cost.
Plus rumours that the German and Spanish translations are completed by not released.
They are probably wondering if they can get away with releasing Spanish, German, French and so on as digital only. They may have no other choice.