BCRYPT - Why doesn't the Linux Distributions use it by default?
A couple of reasons:
The BCrypt-based scheme isn't NIST approved.
Hash functions are designed for this kind of usage, whereas Blowfish wasn't.
The added security is BCrypt is based on it being computationally expensive, rather than the type of algorithm. Relying on computationally expensive operations isn't good for long-term security.
See http://en.wikipedia.org/wiki/Crypt_%28Unix%29 for some discussion on this.
OpenSUSE 11.4 (at least) does use Bcrypt by default.