>>211937809creators got bogged down with other shit at the time and before they even realized there might be something, the walking dead got the ball rolling.
other book and comic franchises began flooding the market, attracting writers to those steadily growing products.
compared to that you had one notable flick from the early 2000s with its only gimmick being fast zombies, a follow-up that, while not utter shit, is still mediocre at best and a year spanning indecisiveness and preoccupation with other projects by the creators, a perfect recipe for the 28 days franchise to remain canned in the foreseeable future, until they eventually got around and got to plan the next part.
so the main problem is missing source content, had it been a comic or novel with rich lore it would very likely have been adapted by some studio and turned into a money printing machine.
then again there'd always be the risk they'd turn it into a pile of shit if boyle wouldn't be watching over it closely.