Some movies have a long production cycle, but this one seems a bit ridiculous. Warner Brothers has indicated their continued interest in a The Man From U.N.C.L.E. film, despite director Stephen Sondheim jumping ship last week. The article claims that Warners has been interested in a movie based on the '60s spy series for tweny years. You have to wonder why. Even the studio supposedly realises there lkely isn't a large and devoted fanbase for the series, yet they've been trying for two decades to get the film off the ground.
For younger visitors not familiar with it The Man From U.N.C.L.E was a product of the early '60s spy boom that resulted from the success of James Bond. It starred Robert Vaughan as Napoleon Solo and David McCallum as Ilya Kuryakin, agents for the fictional United Network Command for Law and Enforcement. Together they fought against the schemes of THRUSH, an organisation bent on world conquest. It was noteable that U.N.C.L.E. was an international organisation, and that the threat from THRUSH so great that an American agent could be successfully partnered with a Soviet agent, years before the real world detente period.
And it's the unfamiliarity of younger viewers with the series that strikes me as the problem. It's these folks that fill the movie theatres for big budget action-adventure movies, not the people most likely to have actual nostalgia for the series. Even more recent properties that have been turned into feature films, like The A Team, haven't been huge hits, and one assumes they have a larger fan base to draw on. And given that much of the premise of the series is tied to the era it was made in it's not hard to suspect that a version set in the modern era will be little more than an original concept with a few signifiers tacked on to connect it with the original. Doing it as a period piece? Not likely, as that might not appeal to the young crowd you need to make it a hit.