Here is the statement of you concerning 5000-80000. Sorry that I quoted you without the reference. It can be misleading, I agree.
“Our Solar system lasts around 15 billion years; that is 15 thousand million years. During this cycle four Buddhas have already appeared with Buddha Gotama the last and Buddha Kassapa before him. There is one more Buddha appearing before the destruction of this Earth. A given Buddha Sasana of a given Buddha lasts from 5000 to 80,000 years. ”
I think what you mean there is that at other times, i.e. when human’s have different life span and different morality, a Sasana might last longer, up to 80.000 years. But not thid one. So the Lifetimes of Sasana is not always the same. Is that correct?
You deduce that from losing the desire to own sensual objects it follows that one will be born only with sukuma rupa. How do you conclude that? I personally cannot see the clear link in between.