[acatton]

Yes, it needs to be done in a fair manner. France used to have a tax (Impôt de Solidarité sur la Fortune) which was anybody with more than X millions of assets had to pay 75% of income tax. (I believe it was 10 millions, but I could be wrong) It wasn't perfect, but it wasn't a bad idea. IIRC it was slashed by Sarkozy right before the 2008 crisis as part of his campaign promises, and he just kept going with his tax cuts on the wealthy after 2008.

Another thing could be multipliers on property tax. For example, you would pay 0.75× of the property tax on your primary residence, 1.5× the property tax of your secondary residence, and start going exponentially on third, fourth, ... residence. Of course, there would be loopholes (like owning properties through companies), and these loopholes would need to be closed.

You could also tax buy-backs and dividends. (If a company buy their own shares, they have to pay a 50% tax on it)

There are a lot of possible implementations that could add up to each other. It's a fallacy to just point at the bad ones and say "look it doesn't work!"

The main issue is that there has been a transfer of global share income from labour to capital in the last 50 years. However we expect to pay for pensions just by taxing labour. It doesn't matter if there are less young people, because (as shown by GDP growth) they are producing more overall, but misinformed politicians use this argument because they don't understand that these folks didn't profit from the increase in productivity. We need to fairly take a share from this productivity increase and distribute it as pensions. The goal is to pay for what we promised, while relieving burden on young people.