You don't understand merged mining because you don't understand why mining exists. The point of it is to secure the coin, not make money on a P & D and move onto the next shitcoin.
+1 (couldn't say it better)
I'ts not that I don't understand merged mining I'm just pointing out that there isn't any appeal
in it for miners. For the coin to be secure it has to appeal to a large number of miners or the principals
need to supply enough hash themselves. The merged coins have so little value they can't make it on their
own so they hook up with a larger coin and feed on its appeal.
No actually you don't understand merged mining. Are you saying Namecoin is not secure? Is Doge insecure? Merge mining isn't because coins have so little value, it's to leverage the security of an existing blockchain and reward miners with no effort or any additional costs.