Giving money to ineffective organizations is throwing good money after bad. I'd love to see competent government that can effectively use funds, but I'm not seeing a lot of evidence for it these days. There needs to be deep reform and anti-corruption efforts. Good luck doing that without the status quo powers pulling out all their dirty tricks.
Taking money away from billionaires just reduces their power, it doesn’t make any difference to the government itself.
And btw, the status quo you mentioned is funded by the billionaires that would be affected by this tax.