Yes, I realise those two statements are in conflict. However, it's still possible for someone earning €200K to not be able to afford to give up €50K a year of gross income to reach the 25 year target I described. High tax, high CoL, a non-working partner and kids can level your chances.

And some costs are just fixed for everyone, so there's a lower limit to consider

The bottom line really is the balance between CoL and earnings rather than absolute earnings.

To achieve a given fraction, R, of your career salary in retirement you need to give up a fraction, S, now. My claim is that most people won't be willing to give up S to achieve the R they feel they need for early retirement (at say 50).

Personally I feel that unless you're 20-25 and have hit it out of the park with a great career starting salary you may as well forget about it and look to retire later... maybe start investing for your kids instead. Give them the 20 year headstart they can't give themselves. Investing for a decade or two longer is the magic sauce