It's just different users developing different solutions. I disagree with the notion that having multiple competing, up to date implementations would "undermine user confidence" in D. Quite the opposite, I'd think.
My point was, I feel like this is a case of different users developing the same solution though.
Sure, it's reasonable to disagree, but I raise it because I have multiple counts of anecdotal evidence from prospective users that it is a problem.
Let's consider more popular languages;
C++ has probably 1000 times the number of users... so I may expect roughly 2000 competing solutions? Nope, there's only one (not even 2).
C#, only one.
Java, there are 2, but the obvious winner is maintained by Red Hat.
Rust, there are 2, and no clear indicator which to choose (same problem).
Etc.
Anyway, I think it's a bad situation, and 3 colleagues have echoed the same sentiment independently. I could tolerate if there were meaningful differences between the solutions, but they're effectively the same solution, just written+maintained by different individuals.
Projects with multiple contributors are usually stronger than single-person projects.
Competing one-man projects shooting it out in the wild-west is not confidence inspiring at all, a single agreed solution supplied by an authority (ie, "dlang.org") or something is preferred. If some enthusiastic user wants to develop a meaningfully superior solution, power to them, but the former should exist for the conservative minds. Most people don't want to experiment, or take time trying to work out which solution is the better or accepted standard, they explicitly prefer to conform, and that should be the easiest path.