Regardless of Mattel's motives, your comment seems to imply you think this decision is a mistake ("not being able to think straight"). Why?
Children don’t care about a skinnier Ken and a disabled Barbie. Not because of the special attributes of these iterations, mind you, they don’t really see these differences yet anyway. Maybe a few parents will appreciate those but that should be about it.
Countless iterations of the same thing is what Barbie was already doing. There's a parody of that in The Simpsons' Stacy Malibu ("it has a new hat!"). This seems a bit riskier and slightly more profound than giving Barbie a new dress. I looked at the photo of the new dolls and they don't look like iterations of the same thing: each looks strikingly different to the rest.
Then again, do people look at Playmobil or Legos and complain that they are "countless iterations of the same thing"? Because they certainly are!
As for the differences: my 2 year old sees them already. And even if not, aren't toys also about teaching something?
> Maybe a few parents will appreciate those but that should be about it
How can you speak for parents and know how many will or will not appreciate this?
The way you phrased this, it sounds like you’re implying that expanding your product line to new customers when your sales are declining is a bad idea. But… I can’t imagine how you think businesses work, then. Like, what’s Plan B? Ride the ship into the ground?