I did a search on the Net about this matter and found out more about this
I hope you did a search on Tintinologist first, as most of this information - plus more - is available here; we have multiple threads about the books, both published an unpublished! ;-)
I'd think that as to the over-all popularity, it's simply down to quantity and quality - there aren't as many, and they aren't as good.
I'm not sure of the importance of the "recentness" of their translation to English - 32 years is a pretty long time! - as I don't think that they have that great a following in the French-speaking world either, where they were available from the start. The books remain available, but that's it, really - no merchandise, calendars, toys, etc., to extend the brand, and no animated adventures to increase their profile with the public. If Moulinsart and the regional publishers don't promote the series, it won't do more than just bubble along.
I do think that with a bit of TLC that they could be revived - a film, perhaps, would be a start, but there could be an archival release of the unpublished version of Le ThermoZéro
, and what preparatory works was done on the unfinished La Main Noire
It's purely speculative, and I may have said it before, but were there ever to be a move towards re-establishing the Tintin
books as an ongoing series, J,Z&J
might be where I would start.
It would allow an entry-point back into the world of Hergé, testing the waters for what might come next. I'd propose that there could be a competition to encourage young artists and writers to develop their style on the principles of Hergé, either through art schools and comics courses at colleges and universities, perhaps with bursaries as prizes, as well as the chance for publication.
To balance some of the sins of the past, I'd promote it as following broadly educational lines, with a positive outlook and a more progressive attitude to issues of race and culture; the father's role as an engineer would allow for science and technology to be looked at, but could be expanded to say that their mother is also an engineer, scientist or naturalist, which broadens the options for stories, and global travel could be a chance to look at environmental issues, or to meet children and people from other cultures, without rendering them simply as stereotypes.
Once a pool of talent in the school of Hergé was available, then perhaps it could at some point be addressed to reviving other series - Quick & Flupke
and lastly Tintin
Were the exercise to prove unpopular, or unsuccessful, then whatever had been developed could easily be retired again, without damage to the Tintin series.