I don't know enough of CDK history but if they bought out some other applications and built out their system,
then
CDK probably patchworked together the different platforms.
I say this because it's not really easy to merge different programs.
example: I have a crm, cms, and ecommerce site all using the same coding language and framework. If all 3 were different at oen time, then the way they did user permissions and a few other things probably it was just simpler to provide bridge code that shares logins and such.
Now imagine using different versions of the language, frameworks or even different technologies like .Net and Java.
There is no way most companies will spend time to fully merge these different products. They possibly might try merging the databases but then again ... maybe not.
Undoing this work isn't that simple either unless this bridgework code is relatively recent but if you have a year of code changes depending on passing data and some features of the other code, it becomes hard too.
Let's not forget that users don't want to have 3 different logins and love the simplicity of 1 login.
TLDR;
Yes, it is doable.
But there is a cost to this.
I think CDK should have just paid the ransom and sucked up the bad luck instead of creating all this bad will and stink.
Why didn't they though? Are they having cash issues?