"Did Jehovah really prove his sovreignty?"
In the theology of the God of the Bible, the basic idea of sovereignty is God's
prerogative. It's all His, including our lives, so it's fair game for Him to
have it however He wants--to give people life that's like heaven, not like
heaven, giving people eternal life, no life, or any amount or kind of life in
between. The belief has it that's basically how they recognized him, wherever
you want to go from there.
"But first he inflicted them with....Couldn't humans have fared better in
living apart from God....?"
I think the common basic idea is a story of people living with divine interven-
tion--they didn't have to have faith God was there and the ruler and provider of
it all, just whether they wanted to commit to Him or not. They chose to not give
credit where due and the indulgence threw their perspective out of whack, they
fell from grace and the benefits of it, and they fared worse.
Wherever you go from there theologically, there's a more general interpersonal
secular point about ethics I can see there, too. People can be selfish and
unethical in interpersonal terms even though they know better--selfishness has
them do it, anyway. To show how far that can go, these two in the story even do
it when living with God regarding God. Beyond a story about God, from what I've
seen some people do, I can believe that some people can be that way.