Salvation Through LDAP?

Since Active Directory is LDAP based, and since many Unix systems support LDAP directories of user information, is this the future for cross-platform authentication???
- Current implementation are strictly ''self-serving" and not focused on solving the problem. For example, Sun will provide an LDAP solution provided that you move all your Windows LDAP to Sun. Same can be said about Microsoft and HP solutions. Linux (and/or Open Source), which has no ''evil" agenda could well solve this problem first! (Samba 3.0)

Since Active Directory is LDAP based, and since many Unix systems support LDAP directories of user information, is this the future for cross-platform authentication???