Even if you get to $3.5 mil, can you just move to Spain or any other place for that matter? Wouldn’t you need some sort of permit to stay long-term?
I know I will never see $3.5 mil, or for that matter, $2 mil! I don't need to, My retirement strategy, is buying lots of lottery tickets!!!!
I have researched moving overseas for retirement. Since I am an immigrant, moved here from overseas, for a better life, it feels kinda counterintuitive! There are websites and organizations dedicated to wannabe expats. There are lists, visa policies, immigrant requirements, best/cheapest places to live, healthcare, etc. Top of the list is Mexico, then Central America (Costa Rica), South America (Columbia), Spain and Portugal. Most countries make it easy for expats, as long as there is proof of income, or buying real-estate, you are good to go.
A couple of months ago, I visited an old college buddy, now living in Bogota, Columbia. I went to my bank here and got 1 million Columbian Pesos for $210. Felt like a bigshot, the 1 million Columbian Pesos, went a LONG way. Yes, living on US dollars, overseas, you are living well!
A three course meal, with a beer, about $8, in a nice restaurant. You can easily live in Bogota, pop.8 million, with the absolute best climate anywhere in the world, for $1500-2000 a month, all in. This includes a full time maid, and a nice two bedroom apartment, etc. If I could just convince my wife to leave her little babies behind. She is waiting on grand kids, then its game over, for our plans.