True, many people can't control themselves which is why, in my country, the government takes your money to give it back to you when you're 67... but I've been raised to be responsible with money so I could pull off retirement as a low spender.
That said, 1M now would be a bit of a challenge, since I'd still have 50 years to go before I die
But still. For example, if I could achieve a stable, low-risk 5% investment strategy, minus inflation and taxes would still net like 30k a year which is still an above average income over here.
The one big risk would be health insurance though, gotta be really careful that you won't get ruined by high premiums in old age.
Anyway, it's just a what-if game. 1M means you have to be careful, but you can pull it off.