I posited a world where flipping a switch was possible and the result was perfect.
All your complaints are about a world where that isn't true, and so are literally inapplicable.
You can argue this is unrealistic, but i'd simply point out the rest is a question of tradeoffs - how fast you do it, what language you pick, etc, there are no perfect answers.
That is no reason not to make progress.
As for practicallness:
In a world of 8 billion people, literally anything you do (something, nothing, whatever) will cause hardship for someone. It's not even an interesting goal to try.
Doing nothing causing hardship.
Moving forward causes hardship.
Combine this with the fact that the unfortunate reality of humans is that one of the main ways that change happens writ large is through seeing the suffering (and success!) of others. I don't think you will change that part of our psychology anytime soon.
The sad truth is we don't all get a perfect, or even good, life. You can't make progress on this, either, without causing hardship to some. Does that mean you should not try?
Because you will never make progress in steps that are only positive for everyone, or even often get the chance to choose who it gets to be negative for.