Your 'logic' says , that you shouldnt use 3DGS , but instead find an engine that doesnt have anything so that you could add everything else yourself...I doubt thats the reason why you use Acknex
If Conitec creates the system your talking about , I doubt anyone would use it. If someone has enough experience in this 'field' to make a MMO network system (even a team of people) why should he use 3DGS and not create his own engine or use another ? What is the reason to use the Acknex engine ?
If you could create your own engine , why should you use an existing body of a car , when you can put your own on the market and sell it as original , and not just a modified car ?

Also , if someone can create a MMO network system , I doubt they cant create what youre suggesting. If anyone is capable of creating a whole system like that , why do they need a 'base' to build on to , when they can just start from scratch with their very own plugin that does the same job...
3DGS is a package that makes things easyer...It comes with a MP system , not a C++ compiler to build your own. I hope you can understand what I'm trying to say