Thank you for even trying to answer my rambles! :-)

I think my contention with the iron is the tipping point and how quickly it goes. Pop-sci tv makes it seem like you fused a single iron atom and bam. Maybe it is you fused an iron atom and it is like a day, a year or a thousand years and that adds up; still bam in terms of cosmic timelines but it is not what I hear when I listen and hear "instant collapse".

Thank you for the thoughts on dark matter and energy as well, and the link on radiation pressure, I will read it.