Dredds box office stateside has been a huge disappointment and its difficult to understand why?
IMO, this is one of the reasons
Is it that nobody really remembers Dredd now, except us aging fanboys?
I think that when Stallone as Judge Dredd came out in 1995, he was at one of the peaks of his career. Almost anything with Stallone in it was 'must see', particularly since his last 3 movies Demolition Man, The Specialist and Cliffhanger were a 'return' from his 'comedy' stints like Oscar & Stop or My Mum Will Shoot.
It was Stallone that promoted Judge Dredd on the international scene like never before.
That was almost 20 years ago (gotta stop realising these things as I feel like like an old fart now :lol - but its true

)
There is no need to outline why Dredd has never lost his appeal here on the board.
However, Prop & Movie Forum members are not what make or break a movie $$$ at the box office.
Take the above into consideration, and I think the reason why the current movie is not doing too well is that Dredd's persona itself lacked promotion.
Big time.
A basic release with little fanfare just didn't cut it with the public it seems.
Say perhaps if they had (as a silly example) shown a trailer with something like 'He's back !' sort of thing, with a very brief visual reference to Stallone and the comics, from a much earlier stage before the release, it would have done much better now.
I am presuming that lack of funds prevented a bigger marketing campaign to 'educate' the new generation.
If say, 'Ghost Rider' was remade in 20 years time using an unknown actor and with little promotion / awareness of character, it too would surely not do well.
Or would Ghost Rider have done so well at all a few years back without Cage ?