It's like building a robot:
"Hey we can build an Asimo
type robot! We have the knowledge and we can put lasers on it. We can improve on it in every way!"
"No, no, no. I just built a marionette with strings and everything. There's more control and its more involved. It's like the original robot."
A few weeks later...
"My marionette's strings are getting all tangled. I've found a way to keep them inline by putting a hard cylindrical cover over the strings."
"The Asimo is proven, and we could do better things with it!"
"No, no, no. MY robot is working better each and every day. People are going to love it.
A few more weeks later...
"I've made it so my marionette can act on it's own...kinda. I made a gear system that allows you to activate the puppet with little input on your behalf."
"So, it's like a worse Asimo?"
"No, no, no. It's just...different.
The last day...
"My marionette is complete! It's made completely of plastic, filled with silicon, and is fully functioning on it's own!"
"You made...an Asimo?"
"NO! It's a marionette! You can't take away my baby!!!!!11!"
In the end the retainer system will look more and more like an AH. But at most it will function like a broken AH, and unfortunately people will make excuses for it.
You can say that SE is improving on the retainers (as I did). But I think there has to be a point where you say, this is a very inefficient system, let's start over.