It truly confuses me how people seriously "hope" there will never be an adaptation of certain series. A good AND a bad adaptation can both result in many great things for a fan of the series. -

First of all, even when the chance is low depending on the source material, it's not IMPOSSIBLE to make a competent adaptation as we have seen times and times before. However, not getting an adaptation eliminates that possibility completely. -

If it turns out well: Jackpot. If it's bad then only the reputation takes a hit, but that's a small price to pay. (Look at how well Tokyo Ghoul is received, despite a horrible adaptation.) -

Additionally the announcement of an adaptation alone can lead to re-popularization of the series. More fanart, more re-prints, people starting it and more talks about the series in general. Ultimately, even the author/artist may profit from it by getting more sales. -

For instance, the Slam Dunk movie announcement has already resulted in more fanart than I've ever seen before. A lot of people have started to read it left and right without me or other people having to push an agenda - all of that BEFORE the movie even aired. -

We have zero information about the movie and still I'm the happiest I've ever been as a Slam Dunk fan.

An adaptation is something to be excited for, not something to be feared of.