If I move to the EU now and take a hit in income, that will become impossible.
If that is true, it's more than I thought it would be and I think if you found a good job you enjoyed, making 80k EUR/yr on top of having $1M saved could give you a secure financial future.
[1] https://www.levels.fyi/Salaries/Software-Engineer/Germany/
$30-40k/yr, pre-tax, would still be ok for one person in Portugal / Spain or other lower cost of living places, right NOW. Once you add in a spouse, children, things start to get hairy.
Once you consider that these places are currently undervalued and their cost of living could increase dramatically in the future, that $30-40k/yr no longer seems as safe.
I would personally aim for $2M+ to feel safe that I won't have to be forced to work a job I hate for the next 30 years.
Insurance for the future. Maybe I get bored of software, maybe I want to take a few years off and not have to work. Maybe I won't be able to "unprogram" the consumerist habits I picked up in the US and will fall back into buying things I don't really need (like Hi-Fi, photography equipment, gaming rigs, TVs, etc...) and will need funds to continue doing that.
I don't know, I guess I spent too much time in the US and deeply concluded that it's better to have wealth than to not have it. I have a lot of reflection to do.
Even adjusting for cost of living, if I bring $1M over to the EU, I couldn't stop working for the next 50 years, I would need a few for $xMs for that.