Wheelguns will never become obsolete or extinct. I have several. My two favorites are my Ruger Security Six and my Smith and Wesson 625 Mountain Gun in .45 ACP.
What I do not have are any 3" revolvers. I have always wanted one. I have a number of 4" and 2", but no 3". There is one that has really caught my attention, but it hasn't been out very long. It is a 3", 7 shot .357 and it comes with an interchangeable 9mm cylinder. I am tempted to jump on it now, but I think it would be prudent to give it a year or so in the field and see what problems, if any, surface. I don't think they will. I have a 4" .44 Magnum on the same platform and it has been great, but it is better to be patient.
There is just something about a 3" revolver that really appeals to me.