In my opinion, trying to pigeon hole a virtual directory as being legacy is flat out wrong. Sure companies use a virtual directory to solve some very classic problems that applications struggle with (such as multi-forest), but that is only part of the reason they deploy. It isn't just about their currently deployed applications, but about their future applications too.
For example, we have some of the largest Fortune 500 companies in the world that are architecting
our virtual directory as a key component in the architecture they are building for the future. They see the virtual directory as vital element that is absolutely necessary to meet their objectives both known and unknown. It is the unknown that kills you in the future.
Think about this for a moment. When Microsoft first deployed Active Directory they told everyone to have an empty root forest, right? Ooops! Later they changed their minds and said nope you don't need that. How many enterprises still have that "old" architecture? How many have multiple forests? Why?
The answer is simple. It is very hard to change. Without a virtual directory, applications are tightly coupled to the data store. This, of course, is a bad thing in any IT architecture. We don't let application developers code directly to the database tables do we? No. We give them a stored procedure or view. With a buffer or "black box" that the applications use, we can now change out infrastructure without impacting the applications.
Our enterprise customers see this and use the virtual directory as their buffer layer or black box. This lets them architect for the future, now. They are using this virtual layer to provide this buffer for both on-premise and cloud. Also, we at Optimal IdM don't stop at just the LDAP support either. For example, with our integration with Microsoft's Graph API we can translate LDAP calls into RESTful web service calls.
Nobody can predict the future. However, when it comes to computer architectures, I do know that we will need to make changes in the future. A virtual directory enables organizations to make changes easier and without impacting applications. The cost savings are enormous and very quantifiable.
So while our customers are deploying the virtual directory on a enterprise scale into the present environment, the key point is that they are doing this to enable flexibility in the future environment too.
That is a key concept that is lost on this person...