If D becomes a failure, what's the key reason, do you think?

[Walter Bright]

Tesuji wrote:
> In article <e8l426$26o3$1 at digitaldaemon.com>, Don Clugston says...
>> It's all in the libraries. D is a fantastic language to write libraries 
>> for. That's where you get the benefit from all the incremental 
>> improvements. If const-by-default enables the creation of much better 
>> libraries, then it's worth the pain. If it doesn't, don't do it.
>> Ruby had this huge surge in popularity not because of the language, but 
>> because of the library Ruby On Rails. Developing good libraries requires 
>> a stable language, and we don't have that right now. The 
>> protection/module system seems to be completely broken.
> 
> Agreed, in addition I also believe that a const-by-default C++ like reference
> type is needed before any container library (like DTL) can be effectively
> written. Currently D is lacking in this area where C++ is strongest. relying
> solely on built-in array / hash is hardly the solution.

I don't understand why either of these would *prevent* effective 
libraries from being built. Neither enables new programming techniques 
or paradigms, they are just aids to documentation and debugging.