To get to the point of, instantly transform my life right now, I'd need $50+ million... Even then it would still be something that must be budgeted wisely to avoid exhausting it.
A million dollars may sound like a lot but when you can spend 2/3-3/4 for a nice suburban home, and the rest gets eaten up by ancillary costs with having something like that. You can see it quickly vanishes... You have a net negative change in your life.
This is why I have to think big numbers for immediate change. Small numbers are all about putting things in place for probable future life changes.
I wonder how far away we are from the point in time when someone "being a millionaire" doesn't really mean much any longer. It used to be that being a millionaire meant you made it and you were set for life. Like you say, that's not really true any longer. Even a regular house eats up a lot of that money and the rest (or even the 1 million) isn't enough to 'just retire' without ever having to worry again.
If I, say, sold a company for enough to where I walked away with that much (after taxes, for the sake of argument) I'd buy a house (not a fancy house either), a car or two, a bass boat, and the rest would go in various mostly long-term investments. I think I'd be pretty settled at that point.
In the US cities, say around 30 years old - most likely $5 million. Rural areas $2 million