What for? Dashcoin brings nothing unique.
Litecoin brings nothing unique. Dogecoin brings nothing unique. Monero and Ducknote brings nothing unique. It is the set of people that makes the coin. The activity of the owners is what gives value.
From the OP:
Why mirror image is better than self sustained fork?
The reason is simple - costs. Self sustained forks demand a lot of development time, if you want to build a well maintained cryptocurrency. And if the network grows, the required development time is likely to grow too.
A simpler, and less costly way to maintain a network with high reliability is to create a self mutating copy of it. Mutating copy is a simple copy of the original source, mutating every time the original source mutates.
Even more - such a process can be automated!
Tell me, what is it exactly that you do?
Scripts, tests, bug fixing and reporting. Suggesting features to make the process better.
Are you seeing just core developers as owners? When I use the word 'owner' I mean every person holding coins. Holding coins = owning part of the network.