Thanks for your thoughtful comment, falconeye. And yes, I do welcome comments and discussion. All articles are opinions based on facts, and different people can reach different conclusions from the same set of facts.
Regarding the point you say I missed, the truth is it is not the scenario we're currently living, and it's unlikely that sensors will become so cheap that their price will be negligible compared to the rest of the camera, at least not in the short/mid-term. I focused on the complaints put forth
now, and my answers are based on the current state of affairs.
Some day, FF sensors will become affordable, but even then APS-C will still be cheaper, so while a FF camera will be accessible to more people than it is now, APS-C cameras will be at an even lower price and still very attractive because of this.
But affordable FF cameras (say, $1000 after price has stabilised) are still far away. I think the
best case scenario is we're 4 years away, but I would bet on 6.
So yes, if cost, size and everything else externally were the same, then maybe more people would choose FF, but this is not the case. Furthermore, APS-C lenses are smaller and lighter than FF ones, and the bodies have the potential to also be smaller and lighter. For some people these are desirable qualities, so even if price were the same, they would still choose APS-C.
Feel free to tell me I'm wrong!
It's what we're here for, to chat.