We need taxes for all - also the super-rich.
"Tax the rich" is an official EU petition. The EU Parliament has to deal with it when successful.
7 EU countries must reach the quorum. And in total 1M Votes are needed. Check yours in the chart and share, cross post etc.!
The petition calls for the introduction of a wealth tax on very large fortunes. Sign the petition here
Belgium has public pensions with a minimum of €1,549 per month (https://www.brusselstimes.com/344282/monthly-pension-in-belgium-to-top-e1500)
You seem to assume that 1.25 millions is supposed to be your only income, but that's not the case.
A really rough calculation (and I acknowledge I could be somewhat off here) suggests that if you contribute for 40 years, and get around 5% interest per year, you'd need to put in an average of €10,000 per year to reach €1,250,000. Working out average salary progression through a working life is left as an exercise for the interested reader, but assuming you're putting 10% of your salary into your pension, you'd need to be earning six figures to make that pension pot, so a drop to around €73,000 including the public pension could be hard to manage.
As I said, not so much can't retire, as can't retire at the same standard of living, especially as annuity payments wouldn't increase with inflation.