The wise amongst us change their minds when facts (or even authoritative opinions) show those strange things to be erroneous.
No-one with authority has ever come out with the facts about the PiZero - its all soundbites and speculation or denials (inc this post)
While it may not be on a datasheet, I thought it was fairly straight forward that they gave specific reasons for the small connectors and lack of the soldered in GPIO header. It was not because they had them on hand. The 3B is made by manufacturing partners, as was every other model. RS and Allied, right? One is using the Sony plant in Wales. Now, the RPi foundation "make" the zero lines in Wales on another line in that same plant on contract. It's made in a simpler process that means it's just a single side board done in a single process line, so they use single process connectors and components. They make and ship these to the official vendors them selves under contract with that plant, so it's like all RPi. What profit they make goes to the RPi foundation. It's all charitable, so the profit margin can be smaller But I am sure it is decent.
This is everything on this cool little board I can remember from the various official releases summarized, possibly incorrectly, but as well as I can do off the top of my head. The above information was in the original release, and were also answers to questions on the forum from actual RPi people, like Liz Upton and others. Any miss-remember-ances are my own and I apologize for them, but it's not just some random speculation thrown up on this thread. You can go back to official releases and confirm most of it. In fact, if you are questioning motivation, they were pretty clear on that too. Dr. Upton tells the backstory, and why in the interview he gave when it was released.
As far as where the zero sits? I've been thinking lately about what a cool classroom board it could be. $35 put's it outside the realm of something for a week long camp or seminar, without bumping the cost up. $10 a piece is almost disposable or swag cost. I was at a conference last year where zero's were being given out as attendance giveaways. You go to a Pi class, here's your Pi to take home with you. There's no reason those adapter cables have to be rare or expensive. Order a box of them off ebay for a little over a dollar a piece.