I am aware of the difference between capital gains tax and corporate tax (also note that not every country has a capital gains tax). My argument applies to both, i.e. one of the reasons for raising inequality is the inbalance of labour and capital and the low corporate and capital gains taxes definitely contribute.
About the effect of income tax on salar, I'm not quite sure what that has to do with my points. I was not arguing that we should eliminate corporate tax and just let income tax handle it. Unless your argument is we should use income tax instead of corporate tax because it lowers salary?
Now it’s true that invested savings become goods and services, capital purchases, etc. for the companies you invest in. But the idea is that government will take over some of that role and invest the taxes collected in more socially beneficial activities, with returns accruing to the public.
Corporate tax is, by and large, a fiction to placate voters. It could (should?) be replaced with a more flexible system that isn't as susceptible to the usual deduction and profit shifting.
1. Spent on goods or services
2. Spent on rent
3. Spent on capital purchases
4. Spent on debt repayment or other forms of financing
In fact income tax does not have the last two points that you admit are bad, so maybe we should eliminate income tax and use corporate tax only?
The thing is low corporate taxes create an inequality between labor and capital gains. It's already the case that wealth inequality is quite unrelated to income inequality, the highest wealth individuals often don't register in the high income brackets.