I actually like where this discussion is going (not really the language being used) so I thought I would interject a few thoughts.
People are free to choose whether they want to invest in the series or not. These days longer anime series are a harder sell. Period. With Funi streaming a good majority of what's on the DVDs on their website it's not like people don't have enough material to test out the series before they invest in it.
I do have some concern on the whole tight lippedness on the status of Season 4. Not because I believe something went wrong with the rights but only because, as of late, Funi has been very conservative on how much of a show the license. There used to be a point in time where Funi would make proclamations about always "finishing" any show they got the rights too, but these days, they seem to have realized their own limitations. The industry is shrinking and even successful companies can't make the same investments into series like they used to.
While Case Closed is the obvious answer. There's also Kodocha, Big Windup, Sgt. Frog, and Shin-Chan. From what I understand the later two (especially Shin-Chan) did reasonably well but Funi pulled production on these shows indefinitely because it was still a risky venture to put out more. Even TV exposure doesn't guarantee a successful DVD release or else Viz's Monster would have been much further along.
Us being One Piece fans we're often blinded by the reality of the circumstances surrounding the anime industry in America. I'm not saying the One Piece on DVD is going to fail, but, if for some reason things seem to halt after the final volume of Season Three I'm not going to cause a ruckus. I was into the show long before 4kids tainted it, and I have the means to still be into the show if anything should happen to Funi's rights to the series. I have loyally supported the commercial release in all its formats (DVD, video games, comic books, and the simulcast) but if it simply isn't enough I'll just shrug my shoulders on move on.
O-chan