It is an industry standard but you're at risk of over stating things there. There's plenty of other federated directory services available that support LDAP and

It is an industry standard but you're at risk of over stating things there. There's plenty of other federated directory services available that support LDAP and SAML, eg https://ldap.com/directory-servers/ https://ldap.com/directory-servers/ What Microsoft Active Directory buys you is easy integration with other Microsoft products like Windows; which is also a de facto standard in most organisations. However go anywhere that is a UNIX, Linux or Apple shop and Active Directory quickly becomes the wrong tool.