By using progressive taxes, either wealth or income, those who benefited from the current system get to keep some of those excess benefits, while keeping less than they would under a no tax system.
No, I mean real resources as in tangible ones. Although in this case I'd also be interested in redirected labour even though that isn't really a tangible asset. Like if you were explaining to someone who didn't speak english and you had to point at the things that the wealthy control that you want to tax away from them, what real objects do you point at?
[0] https://en.wikipedia.org/wiki/Resource#Tangible_versus_intan...