France's government expenditure is 57% of its GDP according to th OECD. It's probably an all-time record in the annals of global economic history in peacetime. It's more than the late Soviet Union spent around 1985-1990 according to the IMF / World Bank.

The 2025 deficit ran at around ~150 billion euros. The Zucman wealth tax would raise 25 billion in the most optimistic projected scenario (so, one sixth of the deficit at most). This is the very best case as projected by its proponents - there's a decent chance receipts would be significantly lower than that.

You're absolutely right that right wing parties did not, and almost certainly will not, solve any of these issues. Neither will a wealth tax. In my opinion, this is only solved in a bang.