Why membership provider is not generic?

I have to confess that I hate membership provider. The default implementation is not very appropriate normally and I haven't seen so far a good implementation of a custom membership provider, probably because this is not possible :-)

So the question is:

In your opinion: which are the reasons for not having membership/role provider as a generic class? I mean, why Microsoft 开发者_C百科didn't select this approach.

EDIT

Reading the answer I realized that maybe it wasn't clear enough that I'm talking about MembershipProvider and RoleProvider. NOT about the core authentication mechanism of ASP NET.

The most obvious reasons that come to mind are:

• The default classes are sufficient for most purposes (mainly: user management, authentication, and permission checks);

• The system is already extensible through inheritance (implement IPrincipal).

• The membership system was designed for the .NET 1.1 Framework, before generics were available.